Detection of spin-orbit coupling of surface electron layer via reciprocal spin Hall effect in InN films

Abstract

Swirly photocurrent in InN films arising from reciprocal spin Hall effect (RSHE) is observed under normal incidence of circularly polarized light at room temperature. It is found that the swirly current is a superposition of the RSHE currents from the surface and bulk layer of InN. The effective spin-orbit coupling coefficient (SOC) in the surface electron layer is suggested to be of opposite sign to that in the bulk. The results constitute a comprehensive understanding of the role of surface electron layer in spin transport in InN. This work reveals an approach to explore spin-orbit coupling in systems like InN.