Spin-orbit interaction from low-symmetry localized defects in semiconductors
Oleg Chalaev1a, G. Vignale1 and Michael E. Flatté2
Department of Physics and Astronomy, University of Missouri - Columbia, MO 65211, USA
2 Optical Science and Technology Center and Department of Physics and Astronomy, University of Iowa Iowa City, IA 52242, USA
Accepted: 12 March 2012
The presence of low-symmetry impurities or defect complexes in the zinc-blende direct-gap semiconductors (e.g., interstitials, DX-centers) results in a novel spin-orbit term in the effective Hamiltonian for the conduction band. The new extrinsic spin-orbit interaction is proportional to the matrix element of the defect potential between the conduction and the valence bands. Because this interaction arises already in the first order of the expansion of the effective Hamiltonian in powers of Uext/Eg≪1 (where Uext is the pseudopotential of an interstitial atom, and Eg is the band gap), its contribution to the spin relaxation rate may exceed that of the previously studied extrinsic contributions, even for moderate concentrations of impurities.
PACS: 71.70.Ej – Spin-orbit coupling, Zeeman and Stark splitting, Jahn-Teller effect / 72.25.Dc – Spin polarized transport in semiconductors
© EPLA, 2012