Materials Research Activities

Mildred Dresselhaus interview, un-edited

Mildred Dresselhaus

Institute Professor at MIT

Interviewed by Bernadette Bensaude-Vincent and Arne Hessenbruch, 25 October 2001, at the Dibner Institute, MIT. Transcribed by Helena Fu (mostly) and Arne Hessenbruch.

The following transcript is as yet un-edited and not reliable. It should be thought of as raw data, and is only put up on this website because I (Arne Hessenbruch) consider it better to have raw data than no data at all. The transcript will be edited in due course.

  • An overview to the transcript is provided by Bernadette Bensaude-Vincent's notes.
  • Prof. Dresselhaus' homepage


Bernadette Bensaude-Vincent: So, we want to focus on certain materials on this site, because we want to discover, especially because it's imploding or exploding and one major problem, we have always put some stuff on on solid state batteries, intercalation compounds that you know very well.

Mildred Dresselhaus: Yes, I know my contribution to the battery business is much more limited than the big deal of intercalation physics

Bernadette Bensaude-Vincent: Yes, and also you've been working on superconductivity and especially materials when it was quite unusual and in the 1950s, so if you could just tell us, try to remember, the situation with superconductivity in the late 1950s when you came to Chicago University.

Mildred Dresselhaus: OK so that's where you want to start... well that's kind of the beginning of my foray into materials science. So I was a graduate student at the University of Chicago and looking around for research topics because at the University of Chicago at that time the students worked very independently. They found their own topics and figured out how to work them out and they basically did everything, sort of, very much different from today. But I was a special case, so I did it even more independently than others who did it independently. It was a little bit of a sociological thing, I don't know if the history of science, you like to have a lot of things that we don't report in our regular papers. I had an advisor that believed that women should not be graduate students, and that it was a big waste of resources to have us, there were very very few of us at that time, about two percent of the graduate student body nationwide - in these fields. So, because I got so much harassment from him, I stayed away from him therefore I worked a lot more independently than I would have, so I didn't have many people to go to to ask questions. He was the only advisor for materials physics or solid state physics. Well I stumbled upon this field partly because of a visit of Brian Pippard who came to the University of Chicago in 1955 for a year to work out the Fermi Surface of Copper, which was a big breakthrough, it was how to do an experiment back then to predict in detail and also measure what was there. So he was there, and he was a big man also with superconductivity at that time, so he interacted with me a lot for the year I was there and we started on this project, he gave me a bunch of ideas which was very helpful. So it wasn't that I was totally in a vacuum because it started out with an interaction. Then he left, to go back to Cambridge University, and I stayed on and we had intermittent contact by letter, or maybe we had three or four letter exchanges until my thesis was done so it wasn't very much. But for me, I learned, and reading the papers that he and others had written that you could measure something about superconductors by measuring microwave properties. So that's what I learned from him and then formulated a problem to see what a magnetic field does. As you know magnetic fields kills superconductivity at the transition temperature you put on a high enough magnetic field, it's the end of the superconducting phase, it goes normal. So my project was to monitor what happened on the way to ending superconductivity, on the way to the phase transition. And so I measured several materials, my main material was tin because it was a convenient temperature range and you could make the samples pretty easily. But I also studied other samples.... (turns off machine). Okay it's off. So I had magnetic field and different superconducting materials with different transition temperatures therefore also critical different magnetic fields. I did different orientations of the magnetic field. You know all the various things you might think of, but I was stuck with one frequency range, because when you build microwave apparatus you're in one frequency range because everything hooks together and this was all homemade equipment because I had no money. But that was the time that you made your own equipment, It was all war surplus stuff that I found in some kind of stock room and throw it away here or there, and most of my equipment was like that, the rest of it I just made in the shop. So I learned how to do that get people in the shop to get me some instructions.

Arne Hessenbruch: So you did have help on that score at least.

Mildred Dresselhaus: No, I built it myself and designed it, but I had instruction because I never built equipment, I was just a graduate student I never was learning how to do all of this. But people were very helpful, so I got a lot of training like that, but that was the way we did a thesis in that time.

Bernadette Bensaude-Vincent: And did you have any idea of the BCS theory? No it wasn't yet, no that came at the very end. So I go along here and I came up with some results that were somewhat counterintuitive. Because I expected that when you go from here to there it would be a continuous thing but instead I'm going toward the normal state before it got to the normal state it got sort of more superconducting, before it went normal. So it was a kind of anomalous effect, and I saw it under many conditions and it always would seem to be there. And that was before BCS. I had all these results before BCS and then BCS came out, and BCS had nothing to say about anything anomalous like this, so Bardeen was actually very interested in my results, because it couldn't be explained by his theory. Bardeen is B of BCS, a Senior person. So he invited me down to University of Illinois to talk to BCS. But I gave a colloqium there as a graduate student which was pretty amazing, and I just remembered that because I just did a lecture series earlier this week at the University of Illinois, and I could tell them I was there in 1957 giving a lecture, and that I'm still alive and kicking. They were kind of interested in that. So, well he got interested in my effect and he gave somebody else a project of trying to develop a theory, a detailed theory of application of BCS to microwaves and magnetic fields, et cetera. So it started a research direction for him, and from the experimental side, Pippard was surprised at what I got so he assigned this project to two other students both of whom became probably people that you're interviewing, became well known in their own right.

Arne Hessenbruch: This was back in Cambridge then, right?

Mildred Dresselhaus: Well it's a little more complicated. One of them was Paul Richards, who was an American who happened to be there, he may be on your list of people that you're interviewing. He was a postdoc, maybe he was a graduate student, I think he was a postdoc at the time, working in the Pippard group. So he did it at one frequency and Brian Josephson was another person probably on your list, he did it at another frequency after Richards. Paul Richards was, after me, he did it at a different frequency. One did lower, one did higher, something like that. They got basically the same results, more or less. Of course different frequencies, different circumstances. So that was what happened and now their results spilled over into the 1960s, and my papers were published by 1958. They went on for maybe another three years,in different frequency ranges doing complementary experiments. But what happened to me, I didn't stay with this project for very long. I wanted to do more with it and I tried to develop some model with my husband who I got married to in 1958. So we worked on this, I don't know that we really got a good model, we didn't get a model for it, I would say we tried to follow up and improve what we had done.

Arne Hessenbruch: Sorry, your model, did you incorporate BCS and then try to also explain the effects from your experiment?

Mildred Dresselhaus: Yeah, what we were trying to do, take into account the details of fields and external fields, and we had RF fields and external fields. We had different directions, RF fields and external fields.

Arne Hessenbruch: So what was your model?

Mildred Dresselhaus: I don't remember a whole lot about what we did at that time. So many years ago! And part of the reason I don't remember so much about it is that it didn't really have a big impact on anything. And for me, I had to switch fields, because when I got my next first job that was at Lincoln lab, I was told that that wasn't an area to work on because everything was solved. Of course my problem wasn't solved but it turned out that it was actually solved by somebody maybe ten or twenty years later quite a long time later. And it turned out to be kind of an obscure, not so interesting effect that didn't have that much to do with BCS theory, but had something to do with the intricacies of all of these things interacting and the internal perturbations between them. But it wasn't an important effect as far as electromagnetic theory and it was not an important effect about superconductivity although a lot of people's attention was attracted and there was some good work that was done, that is the electrodynamics of BCS was worked out as a result of this. But that stood its test of time, was around when later on high-TC came along and gave another push looking at these things. So I moved off into a totally different field.

Bernadette Bensaude-Vincent: Who told you that you had to work on another field?

Arne Hessenbruch: Did you choose it yourself?

Bernadette Bensaude-Vincent: How was the prevision of working on this field formulated?

Mildred Dresselhaus: Well, you start a job, and you discuss what you're going to do and they were very delighted to have me, to do pretty much anything I wanted. I was working in a defense lab, you know Lincoln Lab was a defense lab, and they had a whole bunch of different projects that they had to get done. But they had a few people like me that could do anything they wanted in sort of the basic research area, we don't have jobs like that, so it's hard to explain to somebody what I was doing. But when somebody needed some advice about some solid state physics topic, that was working on some kind of defense project, so they would come around and I'd tell them what I knew about it, that was sort of the way that part worked. So I had a lot of freedom and so I came around there, I saw what people were working on, and it was just so many exciting things going on. This was really the heyday of solid state physics. I arrived there in June 1960, these were wonderful years in solid state physics. Lasers came along in 1960, and in fact, most of the people in the division, solid state division, went to work in lasers. But I didn't, I was one of the people that had so much freedom, that I didn't even have to do lasers like when everyone else had to do lasers, was sort of doing what they wanted, but was urged to go into lasers, but I didn't do that. So I started in this magneto-optics business because I thought that this was a really hot topic and I was right. So I learned totally new technique, I didn't know anything about it, and so it was a lot of new things that I had to learn to do all those experiments.

Arne Hessenbruch: What's the new technique?

Mildred Dresselhaus: Well, optics, I had never done optics before, and it was magnetic field research, well i've done magnetic fields, but that was little tiny fields that I worked with, that I was doing superconductivity work with; 1000 Gauss was as high as we went. These are little solonoids was all I worked with, and I had a chance to work in that high field facility, that was just, just beginning to come online. That was a very good research direction, I worked in that field until the Magnet Lab disappeared from MIT, mid-nineties. So I worked in that area for many years, not necessarily magneto-optics, I worked on a lot of things with applied magnetic fields. So this career change that was imposed on me was wonderful, it was an exciting field, it's good when you're young to work in areas that are new, and maybe superconductivity was not as active at that point. Now when you turn around and look at high-TC superconductivity, We could have discovered it at that time, because I knew about this, and my almost next door neighbor was John Goodenough, who was working on just those materials that were involved in High-TC. And we talked to each other but we never worked on any project, because it wasn't, I wasn't supposed to be working with him. No, we didn't have an idea to try his materials, down at low temperatures with the superconductivity, no one had an idea like that.

Bernadette Bensaude-Vincent: How can you explain, because you tried a lot of materials, you were free...?

Mildred Dresselhaus: No, I didn't try a lot of materials, I wasn't doing superconductivity. I made a switch to semiconductor physics basically at that point. So I was doing something different, and he was working with highly correlated materials. But not only studying magnetism, not studying superconductivity. that was.... But very very soon, after I learned of what they were doing I moved, I didn't want to work in the same areas that everybody was working on there was quite a large group, and most of them were doing very similar things. To me, the physics was not different, of course every material has a little different materials science, but there were no really new concepts, not much, it was working out a lot of details for each new material, which I could do. But I decided that I didn't want to do that, so that's how I started into graphite. My first work in graphite was maybe 1961 could have been the end of 1960, but 1961 for sure, and I've been there ever since, as you know. But I got the idea, there were several events, you know you never write about this exactly, so this is history of science. There were several events that happened in 1960 that made this all possible, and for some reason, I happen to know about some of this. In the UK, there was this discovery of how to make HOPG: Highly Oriented Pyrolytic Graphite. To do the experiments that I needed to do with the high magnetic fields we had to have samples that were a little bit bigger than the flakes of graphite that are normally found in nature. So the materials science of this project was worked out in the UK.

Arne Hessenbruch: What did they come out of? Was there an industrial interest in this or what?

Mildred Dresselhaus: Well, different bases of carbon were interesting in 1960 because that's what I was going to mention to you, the year that diamond was artificially synthesized. So there was interest in the phase diagram of carbon, D: and perhaps the work in Opaloda in making HOPG was related to ...

Arne Hessenbruch: Do you know what the institutional setting was?

Mildred Dresselhaus: Yes, certainly, that was Imperial College in England, London, and I had occasion to visit him very very soon thereafter because there was a conference. The conference where the Josephson effect was announced, maybe, could have been that one, or could have been one before that. But I happened to be in the UK, and I dropped in at Imperial College and we met at that very early time, but when we met I already had quite a number of results. So we had something to talk about, because otherwise he wouldn't have been that interested in meeting a young person whom he didn't know anything about. So one thing was the material, and the second thing was there was kind of an interest in the field of carbon. Carbon became interesting when it was understood that were different faces... it wasn't only graphite which people had known well people knew diamonds but they didn't know how to go from one to the other, that wasn't really understood.

Bernadette Bensaude-Vincent: Were they trying to make carbon fibers over there?

Mildred Dresselhaus: The carbon fiber business came a little later, and my entry into it came later. If you want to go into that, I can, after. But maybe we should talk a little bit how the experiment started because that's never written up anyplace, so you might find some of that interesting. So all the different carbons that I tried because Raytheon was making carbons for, I don't know, military purposes, and the space program was already starting around that time and carbon was a lightweight material so there was quite a lot of interest. I tried some of their graphites but they didn't work, they just didn't have enough good crystalline quality. To do the experiments that I was after an electron has to go through a whole cyclotron orbit before being scattered, that was the criteria. So if you have defects, impurities, whatever, that would interfere with that process. So I needed to have a high-quality crystalline material. Maybe a single crystal would be good but it wasn't big enough to get enough signal. I was looking for small effects.

Arne Hessenbruch: You're doing a magneto-...

Mildred Dresselhaus: Optics, experiment. Well see I started out in the beginning doing my first couple of papers were magneto-optics and what other people were doing and that was kind of my learning experience. and then I took a sidestep and I started another area which people considered too hard so we had virtually no competition because people considered the system too hard. It had a whole bunch of couple bands, four bands, and all people at that time only were thinking about two bands, valence and conduction bands. Anything beyond that was too complicated. So and the experiments could have been tough because it was a materials science problem and all that. But my materials science problem was solved by Opaloda, and there was a fellow at General Electric Laboratory that I found out about in 1960 and he was working in the US with this process of Opaloda. He followed the original work and he made me a sample and the first time we tried it it was beautiful So we were launched. So that might have been the beginning of 1961. We began to get a lot of spectra. Then we tried to figure out what it was that we were seeing. We now had a theory problem. Unfortunately, I don't remember exactly how this happened but when I was a graduate student at the University of Chicago one of my colleagues, maybe two years older than me, but somebody I knew pretty well, was Joel McClure. He figures into this picture because somehow I made contact with him because he had moved into this graphite area, he wasn't doing that when he was a graduate student, but he became the person that developed the theory for the energy band structure of graphite. So we made contact and I remember him visiting me maybe the fall of 1962, before my third child was born. We were talking about how to deal with the band structure of graphite, explained all the spectrum, and I really got a lot of seminal ideas from him. My husband Gene understood immediately how to translate what he was doing to the experiments that I was doing. We developed a theory, and for our case adapted what McClure had done and extended it to explain the experiment and it worked very well. And so we were able, for the first time at that time to understand many of the details about the electronic structure of graphite. So that was 1962 or so, and I remember publishing a paper the first time this became kind of known on the outside was I was invited to an IBM conference, I don't know exactly the dates of that, but it must have been either late 1962 or early 1963. And that paper is published in the proceedings of the IBM journal. The IBM journal had a special issue for this particular conference and it was my paper on the Fermi surfaces of graphite. So that was one of the very early papers on Fermi surfaces of graphite, and we learned a lot of things. You know that it wasn't just ellipsoids that had more things associated with it and that was, we really did very detailed things with it. And actually what we did that was interesting and new and inspired by the work of McClure but also kind of different is we had some kind of model that is still used today, basically. But it changed, I'll explain all the changes that happened because that's an interesting story for history of science maybe. So we have electrons in holes in graphite, and they were understood at that time and then I... See every year, science moved slowly in those days, relative to now and I think we wrote a lot of papers on different aspects of this always getting better. Then sometime in the mid-1960s my very first graduate student, Sam Williamson and we did cyclotron resonance and DeHofstadt-Alfven effect, all of those things explaining about the Fermi surface. So we brought to bear all the different experimental techniques we could think of to look at this, and Sam Williamson went on to a very distinguished career. And he has a similar position to what I have at NYU, institute professor is my title here. He has similiar position, but that was my first student. But his claim to fame isn't this, although his thesis I think was really very good but he had an interesting career, he went to Rockwell International, got into semiconductor physics, like many of us did and superconductivity after that, and SQUIDS, magnetometers, came in at that time so he learned that technique and he had the idea just around 1970 of using that technique to look at the human brain. That's how he's known, a big name in brain science, using this technique. Yes, but related to what we were doing back, not so far off from what we were doing together in the late 60s. And my second student after that we went, maybe he was my third student, but very early times, we had the idea that if we took polarized light, doing the experiment in polarized light rather than circularly polarized light, we would be able to look at specific transitions, linear. Electrons go like this and they have different charge, the electron goes this way, the hole goes that way and they rotate in different ways, so we would be able to separate the transitions, and as soon as we did that everything fell apart because what we thought should have been electrons seemed to be holes, and what was holes seemed to be electrons. So this was pretty crazy, so basically the result of doing that polarized experiment, we found that everything that had been done on the electronic structure of graphite up until that point was reversed. That the electrons were holes and holes were electrons. Which was very sensible on the basis of fairly elementary considerations. That's why we thought that we were right, so when I submitted my first paper on this subject to the Physical Review maybe it was Physical Review Letters, I don't remember exactly, but one of those journal articles, the reviewer was Joe McClure. And he was an obvious reviewer of this kind of paper, because he is a most knowledgeable person. And he revealed his identity; they're not supposed to do that, but he revealed his identity. And he told me, "You don't want to publish this, people have been doing for the last twenty years all kinds of work with electrons this and holes that and how could you reverse it? You must have something wrong with your experiment". So we checked and we checked and we checked and we said to him that "we think that we're right and if we're wrong, OK, we'll take our chances". And we went ahead and we published it. And as soon as it came out, the paper came out, we started getting letters and comments from different people. "So this is the explanation of this effect, and this is the explanation of that effect", and they had all these data in their drawers and they wouldn't publish them because they couldn't understand what was going on. A: The Emperor's New Clothes! And then when we straightened out the electron/holes everything started fitting into place. And I had the real pleasure, so this is 1968 or so when we discovered that effect. In 1972, or maybe it was 1970, they had an international conference on low dimensional materials in Dallas, TX. And Joel McClure gave the invited talk on semimetals, or graphite semimetals, something like that. And he focused the entire talk on turning the electronic structure of graphite upside down bringing everybody's work, well we had done that also, but he did it on this occasion for everybody, and it was a very nice thing. And at that time, I gave the corresponding talk on the group V semimetals business because we had been working on that as well, in those early days, working out the electonic structure, the relation of all the group V semimetals. So that was kind of that early period when I was in magneto-optics. I was already at MIT because I joined the faculty in 1967 So 1968 when we turned the band structure of graphite upside down was my first year on the faculty.

Arne Hessenbruch: I wanted to ask you about the beginnings of the Interdisciplinary Laboratory at MIT. We actually talked to John Goodenough and I asked him if he had anything to do with it and he said "no, no, no, sitting out there at the Lincoln Lab, there was nothing", and it was almost a hostile atmosphere, they didn't want to have anything to do with him.

Mildred Dresselhaus: Well, I was kind of a part of it. Let me give you a little background. You may have some difficulty but some of the people are still alive. The person who really started all of that was Arthur von Hippel. It's hard to interview him now; you missed your window with him. He will have his 102nd birthday on the 19th of November [2001]. But he was a big factor in my early life; he really liked all the things that we were doing. Now, when you're a young faculty member – a young female faculty member it's maybe not so easy. But to have people who appreciate what you're doing makes things a lot better. So, he was always a good friend. Of course he escaped from the Nazis and all that. He came to the US. He came here, maybe '36 or '37, many years before me, and he started the Interdisciplinary Laboratory, which grew. They worked on many things, properties of dielectrics. See, we had this common background. That's a little bit how we met in the early times. They had ferroelectrics, piezoelectrics, they were growing crystals of all kinds, and phases of ice. There were a lot of books written. He was a big influence on the early solid-state physics. It's too bad because he was coherent until about five years ago, '97 or '96. He knew everything still. He was with it, but now he doesn't even recognize me. I think this is off-base, but there may be some people who know details about the lab. There's John Gelatis who is a microwave person and worked in this laboratory. He is still alive; he must be in his 80s. He retired a long time ago. He wasn't really a PhD scientist, but he worked in the lab and might be a useful source. He may be able to tell you some other people who may still be alive. Most of the people that I can think of are no longer with us. There's George Pratt, who is faculty still, who came to MIT before I did and had quite a lot of contact with von Hippel, but I don't think he was a member of the lab per se. And he came after the 60s. In 1960, the Interdisciplinary Lab was formed, that I became Director of, but the origin of the lab goes back to the 1936 period and it evolved with von Hippel and he had different groups doing different things. It was his idea.

Arne Hessenbruch: Here at MIT? The whole idea that materials science was all fields was his and he was ridiculed and took a lot of flak for that. But when the war came, the lab that he had and the people that he had were very much appreciated. That was the way to solve problems. So he got very heavily involved with war work. And he was anxious to be that because he had had such a bad time in Europe. A lot is written about this, I am sure the history books... You can find out a lot about it.

Arne Hessenbruch: But you said that when the IDL was set up you were involved.

Mildred Dresselhaus: Well, I wasn't involved. The idea was von Hippel's. I came and started working in the lab in 1960. I was working in the high-field [lab] which wasn't on campus. The high-field lab is not at Lincoln Lab. I was an employee of Lincoln Lab and maybe I analyzed some of my data, did some of the calculations, at the Lincoln Lab, but when I was actually doing the experiments I was here. And it was in the basement of Building 4. That basement of Building 4 is still there. I could show you exactly where that whole thing started. But von Hippel was in a different location: that was the Magnet lab. The Magnet Lab was really separate. The Magnet Lab had people doing all different things, so it was very interdisciplinary in the Magnet Lab. The Magnet Lab had, when I started, maybe a handful of people – we ran our own experiments. In 1962 or maybe 1963, Ben Lax who was my boss got the idea to start something called the national magnet facility and got the funding from the Airforce. They built the building in a bakery over in Albany Street and that became the Magnet lab but the pre-magnet lab, when I worked on it, was in Building 4. When we discovered the magneto-optics of graphite, that was done there, in Building 4.

Arne Hessenbruch: With all this interdisciplinarity, I presume you felt like a physicst. So, when the IDL was started with the name of Materials Science & Engineering, did you feel that this was a strange concept?

Mildred Dresselhaus: No. There were two reasons that I was very much at home in it. When I did my PhD-thesis I did it in an interdisciplinary environment. This will sound very strange to you but I got my degree at the University of Chicago. The laboratory where I had my equipment and where I was actually working was called the Institute of Metals. It had phsyics, chemistry, and metals. It was Cyril Smith, who was boss of the lab. He was the person I knew. It was totally funded by industry. Have you done any work on Cyril Smith?

Arne Hessenbruch: No, but we have his books here in the basement – he bequeathed them to the Burndy Library.

Bernadette Bensaude-Vincent: Is he still alive?

Mildred Dresselhaus: No, no. He died in 1988 or something. He would be a lot older than me.

Arne Hessenbruch: He has left his papers to MIT.

Mildred Dresselhaus: He had an impact on many things. His wife was an historian and the last 20-30 years of his life he did both history and sicence. He was a very interdisciplinary guy. He had been in industry and we had an id atmosphere. I didn't have much help doing my thesis but the people that helped me were from different people of all walks of life. I got people who knew how to do machining, vacuum systems, I got chemists. I used all these types of people that I felt comfortable with. So later at the Lincoln Lab we were also solving all kinds of things, and then you need all kinds of people. So I was very comfortable with talking to people, explaining physics principles to them. That was my function. I was brought to MIT as professor to teach physics to engineering students. I had a mentality already. The physicists here didn't want to teach physics to engineering students. They wanted the engineering students to come and take the physics courses exactly as they were doing it. They made no effort to have the physics have any relevance to what they were doing. This was the year of semiconductors and they weren't teaching the physics in any way related to that. When I came Gordon Brown was Dean of Engineering and he had the idea that the engineers missed out on WWII because they didn't know enough physics, and he wanted it changed by having people trained in physics teaching them, in addition to having experience with the engineering side, which I did. That's why I was attractive to them: because I had this dual background and didn't have a prejudice against engineers.

Bernadette Bensaude-Vincent: Did you adapt your physics course to engineers, and how?

Mildred Dresselhaus: Oh yes, ever since I have been here I have been teaching physics to engineers. I get physics students who come in also. Over the course of the years the physics department's students have moved towards what I was doing, because physics now has a lot of solid-state whereas when I arrived it had nearly none at all. Ben Lax, my boss, was a member of the physics department and he didn't get along very well with the others on the department, so that wasn't a great help in getting this... But he's still alive. You might want to interview him. And he is in order upstairs. He is still working in the lab.

Arne Hessenbruch: Well, we talked to Sam Schweber, who is also working with us on this project, and he has given me an account of the development of physics at Brandeis from theoretical physics asking philosophical questions towards a physics that can be used, towards engineering.

Mildred Dresselhaus: They have focused a lot on theory at Brandeis, but the MIT experience was somewhat different, because it was flavored a lot by WWII. The Radiation Lab, and also the materials group developed. There was a practical side also here. But it was not in the physics department. There was something in the Physics Department, but it wasn't very much. There was John Slater

Arne Hessenbruch: Would you tell us something about your time as Director; if it's not jumping too many years.

Mildred Dresselhaus: Well that's 1977, so it's jumping a lot. I was the 3rd Director and when I took over the Lab was in big trouble; it was about to lose its NSF funding. I had to keep the money coming in. That's what a Director has to do.The first Director was from Physics, the second was from Materials Science, and I was from Electrical Engineering. I did get a Chair in 1973 which gave me some independence and also some funds to do what I wanted. That's how the intercalation work started.

Arne Hessenbruch: Shall we drop the IDL and turn to the intercalation story?

Bernadette Bensaude-Vincent: Yes please.

Mildred Dresselhaus: My first contact in intercalation physics was Ted Gaballe.

Arne Hessenbruch: We have talked to Stan Whittingham, by the way, so we do have that perspective. I don't know whether that helps you.

Mildred Dresselhaus: There was no contact between us for a long time so we both entered it very much independently I entered the field my first contact with intercalation physics came in 1965 or maybe 1964

Bernadette Bensaude-Vincent: That early?

Mildred Dresselhaus: It's not written down, so you wouldn't know. But you could verify it. I got into it through a person called Ted Geballe he is a very well known person in this area. I strongly recommend that you talk to him. He is about 10 years older than I am. because he really knows a huge amount of the early history. he was involved in many, many things in this field he is retired now but works pretty much every day in the lab He discovered superconductivity in intercalation compounds when you add potassium in an alkaloid metal to graphite, it becomes an intercalation compound and he found that these materials were superconducting That's 1965 or 1964. I think it's referred to in my list [on the web].

Arne Hessenbruch: Yes, it is.

Mildred Dresselhaus: Because it was a very important part of my thinking. he knew about my work on the electronic structure of graphite. We hadn't turned it around yet, it was still the old way. But he knew about our magneto-optics work and was sufficiently impressed with that and wanted me to do some kind of experiment that would illuminate what happened to the electronic structure after you made an intercalation compound out of it. Okay? So that was what he wanted. And, erhh, so he invited me down to Bell Labs and we talked and I listened to what he had to say and i put it somewhere in the back of my mind. I didn't have an idea of what the experiment should be, so I didn't do anything and then in 1970 or 1971, there was a paper by a fellow called Moore (maybe something else) an Englishman, I think also from Imperial College He did the first experiment on the Hausser-Alfven effect in one of the intercalation compounds he showed that you could have cyclotron orbits long enough that you could get magnetic resonance data When I saw that I knew that if I did an experiment that was similar with what he did with optics it would ??? We tried to make the samples and did the experiment, and I guess our first experiment would have been done about 1973 Because it took me a little while to find out about this paper I didn't see it the day it was published the reason that I mention this Chair is that doing this experiment was that I had this income that I could use for hare-brain experiments and things that maybe you couldn't get funding for You always try to do an experiment first to make sure that it works before you send off the proposal, because if it's not going to work I don't want to work there either so you do a little exploratory work - I think everybody does It's certainly the way we do it I used a little resources from my Chair to check it out and we got some interesting, encouraging results, so I said well, uh I'll put a student on it to solve it for a season and then of course we had to fund the student with research money so I tried to get money In my career there have been very few proposals that have not been successful because I am really very modest I don't ask for money unless I really need it and have a good idea I think that's the reason I have been successful in getting funding but that was one where I was not successful The comments of the reviewers basically said, that a person with a physics background and my kind of background should not be mucking around with chemistry-related things that were so complicated that we would never understand So there was a big potential barrier put up by funding agencies. I wasn't able to get anything. And those were the heydays when it was very easy to get money. Maybe I got a tiny little bit of money from the Materials Center. but they said: hush hush, don't tell anybody that you're doing this! But I believe that as soon we began to get some more results and publications, I think I got my first grant in 77 so it was quite a few years when we were quite unable to get funding What happened in 1977 was the first conference in intercalation; the first big conference ever. in southern France, Lanapour. It's near Nice. Southern Riviera, very nice! It was a very influential conference it was well attended and had an impact on almost everybody that went there. It revealed what was going on in intercalation physics and chemistry, it was mostly chemistry.

Bernadette Bensaude-Vincent: Who was the organizer?

Mildred Dresselhaus: Jack Fischer. and somebody called Vogel whom you probably don't know he dropped out, he had a company he dropped out of the whole business five years after He was an influential person in making it all happen maybe not so much for the science

Arne Hessenbruch: I am sure Stan Whittingham was there? You must have met him there?

Mildred Dresselhaus: Yes well, we could look back and find out. I believe he was there and there were people from all over the place that was the very first time that I met any of these people - total news for me.

Arne Hessenbruch: Because they were chemists?

Mildred Dresselhaus: No, almost everybody was new to the field. I'd been there much longer, but nobody knew aI was there. Publishing in all these different journals there was no connection and Listening to all the things they said; then I knew what to do. You know, it had a big scientific impact and we came back to MIT and we started working in all the areas I all of a sudden had a really good picture of what was going on in the field and then my students had a very hard time understanding what was going on in the field and I wrote an article now that article must have started about 1978 or very early 1979; I must have been Director of the Materials Center at the time, right? Because 1977, when I went to Lanapour I must already have been Director because I am just figuring out the dates here ehmm so anyway

Bernadette Bensaude-Vincent: So you wrote this article.

Mildred Dresselhaus: You know it takes a while to write these articles. Okay, so the article has a lot that should go like this, and it turned out that it should go like this is the way much of this did go. So that article is still referred to now, if somebody wants to look at the article on intercalation compound they often go to that ancient article that was written very early in the time of the field. Because of that, I was asked to do a similar thing for fullerenes, that's my big black book on fullerenes, and that came from Bell Labs researchers who felt that my pedagogic style was useful for researchers. And I guess they said, "I'm an old lady now, it's ok if I spend a few years studying everything that's been done in the field and digesting it and telling students what to do". But I'd done another one on carbon fibers, since you asked about carbon fibers, I did that one many years earlier.

Bernadette Bensaude-Vincent: So you suggest that this kind of review articles take a lot of time.

Mildred Dresselhaus: They take a lot of time.

Bernadette Bensaude-Vincent: They are very useful to shape a discipline.

Mildred Dresselhaus: Yes, and I had the opportunity to shape a few fields in this way. And the first one was the intercalation, you know at the time I was doing it, I of course had no idea that it was going to affect other people, I did it for my own students because they were working across such disparate areas and it was hard for them to figure out what it is that we were really doing. Because there's a lot of interdisciplinary research, and somebody's doing X-rays, someone's doing magnets, and another ones doing optics or infrared. Many many different things and so they had to learn the field that they were doing, they learned the techniques and so forth and they had to learn intercalation physics and see how it goes together and how it goes together with all the other guys. So having the review article helped a lot and it helped them in writing chapter one of their thesis too. So I found out how useful that was and that encouraged me to write more things like that later on. We were in intercalation physics until roughly 1990. I did a couple more things later on with with fast optics. We did some kind of elegant work.

Bernadette Bensaude-Vincent: And why did you stop?

Mildred Dresselhaus: Why did I stop? Because I got into fullerenes and nanotubes, and their behavior too. It wasn't that ... I didn't have so many ideas, we'd done so many things already, the field had become mature as a result of other people who'd moved in, moved out. But I moved somewhere else and I, everybody's finite, you can't work on everything.

Bernadette Bensaude-Vincent: Do you have students who went, or are working on intercalation compounds because they need the technique?

Mildred Dresselhaus: No, not really, not really, let me explain about that. Maybe when you interview other people on the project, the ground rules are different. I'm at MIT and the expectation of the graduate student here is that they develop a new field, basically. So when I give a thesis topic, we develop some kind of thesis topic every thesis I try to make like they're breaking some really new ground. There's a finite number of things that you could do. So maybe one thesis was on the structural properties of intercalation and we got into some interesting things with electron diffraction and we could do the surfaces. And then Raman processes. But after I finished all of those forays, big things, then I moved to something else. Okay?

Bernadette Bensaude-Vincent: So you moved to fullerenes.

Mildred Dresselhaus: Yeah, well I saw fullerenes as opening up totally new areas so and it's something I could understand in depth because it's only graphite that's rolled up in a scroll, I already knew about that. When I select topics, you know people always ask me, "How do you know what to work on?" This is graduate students, so I say: you want to work on something new that people don't know much about, and so you take your chances, maybe it will develop into something, maybe it won't. But if it does, then you have a chance at doing something that's really quite new. Otherwise, you're just doing the same thing as somebody else did, and that's not really an MIT PhD. Being a thesis advisor here, I'm a little bit limited, sometimes I have some ideas, oh it'd be nice to do this and this, but that's just an extension of what somebody else did, and that's not appropriate for a PhD thesis. So you asked me about why I got out of intercalation physics. Well I didn't have ideas that were big enough and it's hard to find, when you get to the point where the field is mature, it's hard to find these kinds of good ideas.

Bernadette Bensaude-Vincent: And just one more question about intercalation compounds, did you have contacts with the French people in Nantes, Rouxel...

Mildred Dresselhaus: Oh yes, oh yes, I did. Yes. And in fact, still. I was with Rouxel two months before he died. We had an interview with the French TV, the two of us together I don't know, we had some kind of interview, it was in Nantes. They had a conference and somehow they sort of took me one day some place, and he was there, I was with him because he had ... Yes, the French, now I see why you're interested in intercalation physics, and chemistry in fact, is not sort of spread around the globe. There are few countries, the US was a player, for a while it was a big player, but only for a short time. France was working on it long before the US, we had one person here that was at Argonne National Lab who passed away, dear heart, I've just forgotten. But he was the big person, he was a giant in the field, but he was working in isolation. He passed away in 1965 approximately. He was originally from Europe, maybe came during World War II, or because of World War II, something like that. The French were very big, and the Germans were somewhat into it, but not as big as the French. And then the Japanese entered later and stayed longer. They're still there. And they were the ones that really started the battery business or aspects of the battery business in a big way. I think they had some of the very early patents on them.

Bernadette Bensaude-Vincent: Yes, on intercalation compounds. The French are not much interested in industrial applications.

Mildred Dresselhaus: Well, yes, that's right, but the Japanese companies have pursued that. It was the first patent, I think in 1972 and well I remember that.

Bernadette Bensaude-Vincent: One question I would like to ask you because you give a lot of collaboration with the Japanese. Carbon fiber.

Mildred Dresselhaus: Yes, oh you want to know that? Well that happened because of intercalation. In 1980, there were some important collaborations in my career. The first one was not with carbon fibers, it was with Jean Paul Lycee. And that happened in 1970, we were in Dallas, TX, for this conference that I told you Joe McClure explained about the band structure of graphite and I was explaining about the group five semimetals. Well, they had the conference, it was a very small conference, and that evening, one of the evenings of the conference I went to a concert and I was on a bus going from the conference site to wherever the concert was. And on this bus was Jean Paul Lycee. And I had my badge and he had his badge. We were the only people on the bus with the badges. So I walked over and I introduced myself, I was older than him by a few years. It was okay to approach him I thought, and he of course knew who I was, but didn't know me. That was how we met, and then we started talking about our science. At that time he was working on bismuth, or antimon or something like that, and so I heard what he was doing, and I said, "Oh I know about that, and I know about that" and we started working together and we're still working. I just had something from him yesterday, so we're still working together.

Bernadette Bensaude-Vincent: You have been working together on different topics?

Mildred Dresselhaus: Oh, we worked on many many topics, we must have a hundred joint papers. But it started on that bus, going to the concert. And that was the beginning of, later on, twenty years later, of low dimensional thermal electricity that came from that meeting because I don't know if that would have happened otherwise. Because we had a dinner party and he invited somebody from France to meet me, and wanted to talk about the, the French navy wanted to know something about thermoelectrics, they had a guy from the ministry that came, and that conversation started the field, so, interesting thing, but I've written that out for the conference proceedings. Did I cover what you wanted on Endo? Yes, let me tell you about Endo, because he started... 1970 was EC. We met at a conference. And 1980 I met Endo at another conference, and that was the second conference on intercalation physics. The first one was in France in Lanapour, and the second one was in Provincetown, Massachusetts. And he came to that conference, and I was absolutely blown away by his talk on carbon fibers, it was nothing intercalation, well maybe he had intercalated by that time. But what I saw was that he could make these very long thin things and I said that those would be wonderful agents to do transport measurements. I just saw this vision when I heard his talk of all the things that we could do with those samples. And I didn't know that these things existed until that day. And I went up to him and I said, "I just loved your talk. Wonderful! And we should do an experiment together", I said something like that, and we've been working ever since. So we have many papers too. Yes, but my collaboration with the Japanese is much older than Endo. Endo was not my first Japanese collaborator. But he's my first sort of applied. He's in applied areas, the other people that I worked with before are in more fundamental physics areas.

Bernadette Bensaude-Vincent: And when you have collaborated with Belgians and Japanese, would you say that you noticed different national styles in the field of intercalation?

Mildred Dresselhaus: Well, yes, there's national styles but there's personal styles too. Yes, not every Japanese is like every other Japanese and not every Frenchman.. and Jean Paul Lycee is originally from Alexandria. He was born in Alexandria, Egypt, so I'm not sure he's exactly a typical Belgian either. So maybe he is, maybe he isn't.

Bernadette Bensaude-Vincent: It's much more personal?

Mildred Dresselhaus: Well, you know science is a universal language, so we can relate to everybody doing our science; it breaks down all barriers. When I was doing something, I was president of AAAS and I was advocating with Madeline Albright the importance of the state department, this is the US state department, it should have scientific attaches at as many embassies as possible, because that was a ground where Americans at least would be respected and could talk to people. Rather than being hated and staking the battle on military operations. Think about things we could do together, we could, amount this crazy war on terrorism but maybe if we had a way to work with the populations that are disadvantaged, all the money that's spent on the bombs were spent on food, and improving people's living standards, maybe we would be much better off in the end.

Bernadette Bensaude-Vincent: So you still think that science wins peace among the people.

Mildred Dresselhaus: Well it also brings war, all these tools for more destruction than ever before. So it's kind of a double, science has to be used in the right way too. Well I think we're all getting tired, and we have other things to do, maybe we could get together another time after you get a chance to look at what you have, and what you still need.

Bernadette Bensaude-Vincent: Yes, you can go and have a look on the site.

Mildred Dresselhaus: Here? Oh I used to be an advisor, I was on the board here in the institute for two full terms. I was here doing my thing until I started working for the US government, you know I was working for the Department of Energy. So I had to relinquish everything I was doing in the private sector.

Arne Hessenbruch: Why did you participate here [at the Dibner Institute]? Why are you interested in history of science?

Mildred Dresselhaus: Well I was always interested in the History of Science and well I knew so many of these people, I was a student of Fermi, I just gave a talk for Fermi,on being a teacher and well so I gave the talk and I thought I had such interesting material it wasn't scholarly in the sense that I did a lot of research about Fermi but I just told stories that I knew. And I thought maybe someone would invite me to write an article on it because I thought it was, maybe, a little bit unique perspective, I just gave my talk, if people liked it, maybe they would record it, and that's it.

Arne Hessenbruch: So why don't you write it?

Mildred Dresselhaus: Well I don't have enough time. I always do things when I'm invited. You know how it is, we're pretty busy individuals. Well I have been interested in science and I've known just, you know when I started science was so small, everybody knew everybody. I'm talking about my student years, it was just handfuls of people. This wasn't like today, two orders or magnitude smaller. So many of the people that you're interested in, I knew them. Maybe most of them. In one way or another, our paths crossed. Even if we didn't write papers together, maybe we had some influence. But you know when I, I didn't realize it was Dibner, nobody tells me E56, they say Dibner Institute, I say, Oh okay I know that place. I've been here many times.

Bernadette Bensaude-Vincent: Do you think that you could help us to make contact with the Japanese materials scientists because we would like to have a case study of the US, and a case study on France

Mildred Dresselhaus: Are you willing to go over there?

Bernadette Bensaude-Vincent: Yes we would go to interview people in Japan. For that we would need introductions. So if you could be kind enough to give us a number of names and contacts it would be really helpful for us, because it's very difficult, we cannot just come and say

Arne Hessenbruch: Japan requires special entry.

Mildred Dresselhaus: Okay, I'm very well known in Japan.

Bernadette Bensaude-Vincent: Especially in carbon fiber, because it is the topic we would like to investigate and you know everybody in the field.

Mildred Dresselhaus: I do, well I don't, I wouldn't say I know everybody,

Mildred Dresselhaus: I know a lot of people. I think that the book I wrote maybe was helpful. That book is out of print now, they want me to do a second edition. No time. But I'll do it, I'll do it. Carbon nanotubes are so exciting now that I'm- I don't have the time to write a book like the one I did the first time. It needs to go back in the literature for twenty years, I haven't been involved in everybody's doing, just what i'm interested in. Write a book it's a little different, you have to do the scholarly stuff. When nanotubes subside a little bit maybe it's a good time for me, basically if anybody's still interested. Well I'd be happy, what's your time scale?

Bernadette Bensaude-Vincent: I'm leaving on Sunday but Arne is still here.

Arne Hessenbruch: To go to Japan, we were thinking the first half of 2002.

Bernadette Bensaude-Vincent: Sometime in there.

Mildred Dresselhaus: Well, I'll get Endo, I'm going to see him in two week, I'm going to his lab he runs me ragged, he brings me to lecture in two different places in one day and that's my regular schedule there, it's kind of unbelievable because it's long distances and running around, very tiring, and you can't and every lecture is on a different subject of course.

Bernadette Bensaude-Vincent: But you can write on the train.

Mildred Dresselhaus: (laughter)

Arne Hessenbruch: Well thank you very much!

Bernadette Bensaude-Vincent: It was really very rich for us.

Mildred Dresselhaus: I'm not exactly sure what you're after so you'll have to sort of tell us a little bit.

This page was last updated on 14 October 2002 by Arne Hessenbruch.