Intrinsic vs Extrinsic Spin Currents. Old Ideas in a New Light.
Alexander Khaetskii
Institute of Microelectronics Technology RAS, 142432, Chernogolovka, Moscow District, Russia
Spin-orbit coupling brings about a number of interesting effects, one of which is generation of a spin flux
in the plane perpendicular to the charge current direction. 1 ’2 It is a consequence of the asymmetric
scattering by impurities (the Mott effect) which happens beyond the Born approximation in the scattering
amplitude. It has been recently claimed 3 that an analogous phenomenon can exist even without scattering
by impurities, the corresponding contribution being called ”intrinsic”. I have described the electron spin
dynamics in the presence of the spin-orbit interaction and disorder using the spin-density matrix method
and showed that in the Born approximation the spin current is zero for an arbitrary ratio of the spin-orbit
splitting and the scattering rate and for an arbitrary type of the disorder potential. I argue that the bulk
spin current has always an extrinsic nature [1,2] since it appears only beyond the Born approximation. I
have also studied the magnetotransport phenomena in the presence of a classical magnetic field and the
spin-orbit coupling. New interesting features which occur beyond the Born approximation are found in
the magnetoresistance and classical (charge) Hall effect. These features appear because of a generation
of the spin currents in the direction transverse to that of the charge current.
1
M.I. D’yakonov, V.I. Perel, Physics Letters 35A, 459 (1971).
M.I. D’yakonov, A.V. Khaetskii, Sov. Phys. JETP 59, 1072 (1984).
3
J. Sinova et al., PRL 92, 126603 (2004); S. Murakami et al, Science 301, 1348 (2003).
2
Sorting category: De Conducting electrons in condensed matter
Keywords: spin-orbit coupling, spin current
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