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Observation of spin Coulomb drag in a two-dimensional electron gas

Weber, C. P. and Gedik, N. and Moore, J. E. and Orenstein, J. and Stephens, J. and Awschalom, D. D. (2005) Observation of spin Coulomb drag in a two-dimensional electron gas. Nature, 437 (7063). pp. 1330-1333. ISSN 0028-0836. doi:10.1038/nature04206.

[img] PDF (Supplementary Figure 1 The q = 0 spin-relaxation rate as a function of temperature for the sample with Fermi temperature 400 K) - Supplemental Material
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[img] PDF (Supplementary Discussion of the measurement of the q = 0 spin-relaxation rate, and of the derivation of the non-interacting susceptibility of a two-dimensional electron gas) - Supplemental Material
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An electron propagating through a solid carries spin angular momentum in addition to its mass and charge. Of late there has been considerable interest in developing electronic devices based on the transport of spin that offer potential advantages in dissipation, size and speed over charge-based devices. However, these advantages bring with them additional complexity. Because each electron carries a single, fixed value (-e) of charge, the electrical current carried by a gas of electrons is simply proportional to its total momentum. A fundamental consequence is that the charge current is not affected by interactions that conserve total momentum, notably collisions among the electrons themselves. In contrast, the electron's spin along a given spatial direction can take on two values, ±ħ/2 (conventionally ↑, ↓), so that the spin current and momentum need not be proportional. Although the transport of spin polarization is not protected by momentum conservation, it has been widely assumed that, like the charge current, spin current is unaffected by electron–electron (e–e) interactions. Here we demonstrate experimentally not only that this assumption is invalid, but also that over a broad range of temperature and electron density, the flow of spin polarization in a two-dimensional gas of electrons is controlled by the rate of e–e collisions.

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Additional Information:© 2005 Nature Publishing Group. Received 29 April; accepted 2 September 2005. We thank I. D’Amico and G. Vignale for sending us numerical evaluations of their integral expression for the spin drag resistance. This work was funded by the US DOE, DARPA, and NSFDMR. We also acknowledge support from the Fannie and John Hertz Foundation (C.P.W.) and the Hellman Foundation (J.E.M.).
Funding AgencyGrant Number
Department of Energy (DOE)UNSPECIFIED
Defense Advanced Research Projects Agency (DARPA)UNSPECIFIED
Fannie and John Hertz FoundationUNSPECIFIED
Hellman FoundationUNSPECIFIED
Issue or Number:7063
Record Number:CaltechAUTHORS:20150325-092136198
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Official Citation:Weber, C. P., Gedik, N., Moore, J. E., Orenstein, J., Stephens, J., & Awschalom, D. D. (2005). Observation of spin Coulomb drag in a two-dimensional electron gas. [10.1038/nature04206]. Nature, 437(7063), 1330-1333.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:56059
Deposited By: Jason Perez
Deposited On:25 Mar 2015 19:12
Last Modified:10 Nov 2021 20:53

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