Spin Hall effect in a semiconductor two-dimensional hole gas with strong spin-orbit coupling

J. Wunderlich, B. Kaestner, K. Nomura, A. H. MacDonald, J. Sinova, T. Jungwirth

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Semiconductor spintronics is based on the controlled generation of localized spin densities. Finite spin densities in semiconductors have traditionally [1] been generated by external magnetic fields, by circularly polarized light sources, or by spin injection from spin-aligning materials, such as ferromagnets. Recently there has been considerable interest [2] in an alternate strategy in which edge spin densities are generated electrically via the spin Hall effect (SHE) [3, 4], i.e., in a planar device by the current of spins oriented perpendicular to the plane that is generated by and flows perpendicular to an electric field. The SHE has traditionally been thought of as a consequence of spin-dependent chirality in impurity scattering that occurs in systems with spin-orbit (SO) coupling [5, 6]. Recently it has been recognized that the SHE also has an intrinsic contribution due to SO coupling in a perfect crystal [7, 8]. In this work, we study SHE induced edge spin accumulation in a two-dimensional hole gas (2DHG) with strong SO interactions. The 2D hole layer is a part of a p-n junction light-emitting diode with a specially designed coplanar geometry which allows an angle-resolved polarization detection at opposite edges of the 2D hole system. In equilibrium the angular momenta of the spin-orbit split heavy-hole states lie in the plane of the 2D layer. When an electric field is applied across the hole channel, a nonzero out-of-plane component of the angular momentum is detected whose sign depends on the sign of the electric field and is opposite for the two edges. Microscopic quantum transport calculations show only a weak effect of disorder, suggesting that the clean limit spin-Hall conductance description (intrinsic spin-Hall effect) might apply to our system.

Original languageEnglish
Title of host publicationProceedings of the 8th International Symposium on Foundations of Quantum Mechanics in the Light of New Technology, ISQM-Tokyo 2005
PublisherWorld Scientific Publishing Co. Pte Ltd
Pages140-145
Number of pages6
ISBN (Print)9812568581, 9789812568588
DOIs
Publication statusPublished - 2006
Externally publishedYes
Event8th International Symposium on Foundations of Quantum Mechanics in the Light of New Technology, ISQM-Tokyo 2005 - Hatoyama, Saitama, Japan
Duration: 2005 Aug 222005 Aug 25

Publication series

NameProceedings of the 8th International Symposium on Foundations of Quantum Mechanics in the Light of New Technology, ISQM-Tokyo 2005

Other

Other8th International Symposium on Foundations of Quantum Mechanics in the Light of New Technology, ISQM-Tokyo 2005
CountryJapan
CityHatoyama, Saitama
Period05/8/2205/8/25

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

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