Spin Hall effect on the kagome lattice with Rashba spin-orbit interaction

We study the spin Hall effect in the kagome lattice with Rashba spin-orbit coupling. The conserved spin Hall conductance sigma(s)(xy) (see text) and its two components, i.e., the conventional term sigma(s0)(xy) and the spin-torque-dipole term sigma(s tau)(xy), are numerically calculated, which show a series of plateaus as a function of the electron Fermi energy epsilon(F). A consistent two-band analysis, as well as a Berry-phase interpretation, is also given. We show that these plateaus are a consequence of various Fermi-surface topologies when tuning epsilon(F). In particular, we predict that compared to the case with the Fermi surface encircling the Gamma point in the Brillouin zone, the amplitude of the spin Hall conductance with the Fermi surface encircling the K points is twice enhanced, which makes it highly meaningful in the future to systematically carry out studies of the K-valley spintronics.

NSFC 10604010 105340306077606160521001National Basic Research Program of China 2009CB929103 P.Z. was supported by the NSFC under Grants No. 10604010 and No. 10534030, and by the National Basic Research Program of China (973 Program) under Grant No. 2009CB929103. S.-S. L. was supported by the NSFC under Grants No. 60776061 and No. 60521001.