Longitudinal and spin-Hall conductance of a two-dimensional Rashba system with arbitrary disorder
Abstract
We calculate the longitudinal and spin-Hall conductances in four-lead bridges with Rashba - Dresselhaus spin-orbit interactions. Numerical results are obtained both within Landauer-Buttiker formalism and by the direct evaluation of the Kubo formula. The microscopic Hamiltonian is obtained in the tight-binding approximation in terms of the neareast-neighbor hopping integral
t
, the Rashba spin-orbit coupling
V
R
, the Dresselhaus spin-orbit coupling
V
D
and an Anderson-like, on-site disorder energy strength
W
. We reconfirm that below a critical disorder threshold, the spin-Hall effect is present. Further, we study the effect on the two conductivities of the Fermi energy, Rashba/Dresselhaus coefficient ratio, and system size.