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 devices1. 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 themselves2. 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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Awschalom, D. D., Loss, D. & Samarth, N. (eds) Semiconductor Spintronics and Quantum Computation (Springer, Berlin, 2002)
Ziman, J. M. Electrons and Phonons: The Theory of Transport Phenomena in Solids (Oxford Univ. Press, New York, 2001)
Cameron, A. R., Riblet, P. & Miller, A. Spin gratings and the measurement of electron drift mobility in multiple quantum well semiconductors. Phys. Rev. Lett. 76, 4793–4796 (1996)
Meier, F. & Zakharchenya, B. Optical Orientation (North-Holland, Amsterdam, 1984)
Bar-Ad, S. & Bar-Joseph, I. Exciton spin dynamics in GaAs heterostructures. Phys. Rev. Lett. 68, 349–352 (1992)
Rammer, J. Quantum Transport Theory (Perseus Books, Reading, Massachusetts, 1998)
Castellani, C., DiCastro, C., Kotliar, G., Lee, P. A. & Strinati, G. Thermal conductivity in disordered interacting-electron systems. Phys. Rev. Lett. 59, 477–480 (1987)
Yarlagadda, S. & Giuliani, G. F. Spin susceptibility in a two-dimensional electron gas. Phys. Rev. B 40, 5432–5440 (1989)
Kwon, Y., Ceperley, D. M. & Martin, R. M. Quantum Monte Carlo calculation of the Fermi liquid parameters in the two-dimensional electron gas. Phys. Rev. B 50, 1684–1694 (1994)
D'Amico, I. & Vignale, G. Spin diffusion in doped semiconductors: The role of Coulomb interactions. Europhys. Lett. 55, 566–572 (2001)
Kato, Y. K., Myers, R. C., Gossard, A. C. & Awschalom, D. D. Observation of the spin Hall effect in semiconductors. Science 306, 1910–1913 (2004)
Wunderlich, J., Kaestner, B., Sinova, J. & Jungwirth, T. Experimental observation of the spin Hall effect in a two-dimensional spin-orbit coupled semiconductor system. Phys. Rev. Lett. 94, 047204 (2005)
Flensberg, K., Jensen, T. S. & Mortensen, N. A. Diffusion equation and spin drag in spin-polarized transport. Phys. Rev. B 64, 245308 (2001)
D'Amico, I. & Vignale, G. Spin Coulomb drag in the two-dimensional electron liquid. Phys. Rev. B 68, 045307 (2003)
Kikkawa, J. M. & Awschalom, D. D. Lateral drag of spin coherence in gallium arsenide. Nature 397, 139–141 (1999)
Vohringer, P. & Scherer, N. F. Transient grating optical heterodyne detected impulsive stimulated Raman-scattering in simple liquids. J. Phys. Chem. 99, 2684–2695 (1995)
Chang, Y. J., Cong, P. & Simon, J. D. Optical heterodyne-detection of impulsive stimulated Raman-scattering in liquids. J. Phys. Chem. 99, 7857–7859 (1995)
Gedik, N. & Orenstein, J. Absolute phase measurement in heterodyne detection of transient gratings. Opt. Lett. 29, 2109–2111 (2004)
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.).
Reprints and permissions information is available at npg.nature.com/reprintsandpermissions. The authors declare no competing financial interests.
The q = 0 spin-relaxation rate as a function of temperature for the sample with Fermi temperature 400 K. (PDF 1061 kb)
A 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. (PDF 46 kb)
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