Time-Dependent Transport in Gated Topological Insulators

We investigate the transport property of the surface states of a topological insulator (TI) in the presence of a time-dependent potential. We find that the normally incident electrons can be perfectly transmitted through the time-dependent region under symmetrical potential configuration. But the perfect transmission is broken upon application of an asymmetrical potential. The contour plot of the transmission shows a fishlike transmission profile, which varies according to the potential configuration, and the strength and frequency of the time-dependent potential. This distinct transmission characteristic may be utilized to modulate the transport property of the TI.