Efficiency of electrical manipulation on two-dimensional topological insulators

We investigate the efficiency of electrical manipulation on two-dimensional topological insulators by considering a lateral potential superlattice on the system. The electronic states under various conditions are examined carefully. It is found that the dispersion of the mini-band and the electron distribution in the potential well region display an oscillatory behavior as the potential strength of the lateral superlattice increases. The probability of finding an electron in the potential well region can be larger or smaller than the average as the potential strength varies. This indicates that the electric manipulation efficiency on two-dimensional topological insulators is not as high as expected, which should be carefully considered in designing a device application that bases on two-dimensional topological insulators. These features can be attributed to the coupled multiple-band nature of the topological insulator model. In addition, it is also found that these behaviors are not sensitive to the gap parameter of the two-dimensional topological insulator model.