Materials Research Activities

Mildred Dresselhaus interview, Bernadette Bensaude-Vincent's notes

Mildred Dresselhaus, Institute Professor at MIT

Interview conducted at Dibner Institute, MIT, October 25, 2001

The following are Bernadette Bensaude-Vincent's notes from the event.

BERNADETTE BENSAUDE-VINCENT: How did you make the choice of superconductivity at the University of Chicago in the 1950s?

MILDRED DRESSELHAUS: We were encouraged to be independent. Brian Pippard from Cambridge was there for a year and helped define a topic for my thesis. He had been working on Fermi surface of copper. He suggested studying the response of a superconductor in a magnetic field. I made many measurements with various materials in various conditions. And I got unexpected results.

BERNADETTE BENSAUDE-VINCENT: Was it before the BCS theory?

MILDRED DRESSELHAUS: Yes it was before the BCS theory and when I published my results Bardeen became interested in them because they could not be explained by their theory. He gave the problem of finding an explanation for it to someone else. I worked with my husband on the model but we did not get a good one. Somebody solved the problem 20 years ago. It was not a consequence of BCS it was not an important effect for superconductivity.

BERNADETTE BENSAUDE-VINCENT: What was the situation at the Lincoln Lab when you moved there?

MILDRED DRESSELHAUS: It was a Defense Lab there was a bunch of interesting projects going on. These were the wonderful years in solid-state physics. Lasers came. I was given so much freedom that I did not have to work on lasers.

BERNADETTE BENSAUDE-VINCENT: How did you choose your new research topic?

MILDRED DRESSELHAUS: It was a wonderful career change. I started up magneto-optics. There were new techniques to be learnt, optics in particular. I was working at the High Field Lab, in the basement of Building 4. John Goodenough was my neighbor. I wanted to be independent. Each material has its material science. I decided to work on graphite. There was no competition at that time. The materials science on graphite came from the UK. A highly pyrolitic-oriented graphite came from Imperial College in London. The synthesis of diamond had raised interest in the phase diagram. There was an interest in carbon because of its different phases, interesting especially for space programs.

For my experiments I needed a good crystalline structure for the electrons to circle. For the theory problem Joel McClure from Chicago University helped me. A paper was published in the IBM Journal for Research and Development in 1963. Then every year we improved the model. With my second graduate student we turned the established view of the structure of graphite upside down: we put holes were electrons were supposed to be and vice versa. The paper came out in 1968. It turned out to provide the explanation of many effects. It was a real pleasure to hear McClure at the Conference of Low Dimensional Materials in 1970.

ARNE HESSENBRUCH Did you have any connections with the Interdisciplinary Laboratory that was set up at MIT in these years?

MILDRED DRESSELHAUS: I had contacts with A. von Hippel. He was a good friend. The whole idea that Materials Science was interdisciplinary was his idea. He had suggested interdisciplinary laboratories in 1936 and WWII reinforced his view. He started an interdisciplinary laboratory of his own. The Magnet Lab where I was working was separated from von Hippel's. Ben Laks had started a new interdisciplinary lab with Defense money.

I was at home in an Interdisciplinary Lab. My PhD thesis was prepared in an interdisciplinary environment. The Institute of Metals at Chicago University had been sponsored by industry. There were chemists, physicists, all disciplines. The Institute's chair, Cyril S. Smith, advocated interdisciplinarity. He became an historian like his wife in the last 20 years of his life. He did both physics and history.

At MIT, Gordon Brown, the Dean of Engineering, had the idea that engineers should think like physicists. I was asked to teach physics to engineers not in the physics department. This is the MIT tendency to emphasize the practical side rather than the theoretical side.

I had no prejudice for engineers because I needed them for what I was doing. I was affiliated with Electrical Engineering before I got a Chair.

ARNE HESSENBRUCH: What was the situation when you became Director of the MSE Department in 1977?

MILDRED DRESSELHAUS: I was the 3rd director. The Lab was in big trouble because the NSF grant was about to be lost. I tried to keep funding coming in like all directors.

BERNADETTE BENSAUDE-VINCENT: How did you come to the subject of intercalation compounds?

MILDRED DRESSELHAUS: I entered the field in 1964. Ted Gaballe of Bell Labs had discovered superconductivity in alkali metal intercalated graphite. How could it be superconducting when none of its constituent were? He knew my work on the electronic structure of graphite. So he asked me to look at the structure after intercalation. I had no idea of what the experiments should be. In 1971 Moore from Imperial College did the first experiment. So in 1973 I decided to the same with optics.

I wrote a proposal to get funds after some exploratory work. For the first time the proposal was refused. The reason was that my proposal concerned a complicated chemistry that I could not possibly get into: I did not get the money. I received my first grant on intercalation in 1977.

BERNADETTE BENSAUDE-VINCENT: What was the situation in intercalation compounds when you entered the field?

MILDRED DRESSELHAUS: There was an important conference in France at Lanapour (?) near Nice organized by Jack Fischer and Vogo, a company manager who was influential in raising money. In fact the participants did not know each other and they started talking together. This conference had a great scientific impact. I wrote a review article for my students in 1978 that was published in 1981. It turned out to be quoted often, and often because I had few results to report. I pointed out it should go like this and that was the way it did go.

ARNE HESSENBRUCH: Did you interact with Stan Whittingham?

MILDRED DRESSELHAUS: Whittingham was there but I had no connection with him

BERNADETTE BENSAUDE-VINCENT: Did you meet with Jean Rouxel?

MILDRED DRESSELHAUS: Oh yes, I met him in Nantes two months before his death.

ARNE HESSENBRUCH: Who were the leaders in intercalation compounds?

MILDRED DRESSELHAUS: Researchers in few countries are active in this field. The US has been active for a time. France had been active long before the USA and to a certain extent Germany also. Japan entered the field later with batteries but are still there. The first patent was taken in 1972.

We worked on intercalation compounds until 1989. Then I stopped because I did not have ideas big enough. You know the MIT rule: each PhD thesis should be innovative, bring something new.

BERNADETTE BENSAUDE-VINCENT: Would you say that conferences and review essays were crucial in the emergence of this research field?

MILDRED DRESSELHAUS: Yes review essays are a pedagogical style useful for shaping fields. I was asked to do the same for fullerenes and later for carbon fibers.

BERNADETTE BENSAUDE-VINCENT You've had a number of international collaborations. Did you notice different national styles in the domain of Materials Science and Engineering?

MILDRED DRESSELHAUS: There are more personal styles than national styles. Science is a universal language.

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