Optical conductance of a two-dimensional semiconductor in the presence of Rashba spin-orbit coupling and a periodic potential
We investigate the optical conductivity of a two-dimensional semiconductor with Rashba spin-orbit coupling subject to an external sinusoidal potential. Using Fourier series, we obtain quantitative results on the band structure of this system. The periodic potential can be treated as a perturbation of the Rashba Hamiltonian, with the induced band gap at degeneracy point being linear with the potential strength. The optical conductance displays a number of interesting features, namely the presence of multiple tunable resonances that originate from a k-shift of band extrema.