The effect of spin-orbit interaction on optical conductivity in graphene
We present a systematic investigation of the effect of spin-orbit interaction on optical conductivity in monolayer graphene. Our key findings are: (i) level splitting at various crystal symmetry points caused by true spin as well as pseudospin of the electrons gives rise to a resonant current response; (ii) under heavy doping, the spin-orbit interaction leads to a re-entrance of finite conductivity at very low frequency which was strictly forbidden in the absence of spin-orbit coupling; (iii) deformation of band structure and the topological properties of trigonal warping are analytically identified in a low-energy conical-like approximation.
Wang, W., Zhang, C. & Ma, Z. (2012). The effect of spin-orbit interaction on optical conductivity in graphene. Journal of Physics: Condensed Matter, 24 (3), 1-9.