Spin Hall effect in a kagome lattice driven by Rashba spin-orbit interaction

Abstract

Using four-terminal Landauer-Büttiker formalism and Green’s function technique, in this present paper, we calculate numerically spin Hall conductance (SHC) and longitudinal conductance of a finite size kagome lattice with Rashba spin-orbit (SO) interaction both in the presence and absence of external magnetic flux in clean limit. In the absence of magnetic flux, we observe that depending on the Fermi surface topology of the system SHC changes its sign at certain values of Fermi energy. Unlike the infinite system (where SHC is a universal constant ±e8π), here SHC depends on the external parameters like SO coupling strength, Fermi energy, etc. We show that in the presence of any arbitrary magnetic flux, periodicity of the system is lost and the features of SHC tend to get reduced because of elastic scattering. But again at some typical values of flux (ϕ=12, 14, 34…, etc.) the system retains its periodicity depending on its size and the features of spin Hall effect (SHE) reappears. Our predicted results may be useful in providing a deeper insight into the experimental realization of SHE in such geometries.