Electrically tunable valley-dependent transport in strained silicene constrictions

摘要

We adopt the tight-binding model and the mode-matching method to study the electrical modulation of the valley polarization in strained silicene constrictions. The effects of the potential energy, the external electric field, and the strain on the band structures and the transport property are investigated. The conductance shows a clear valley polarization and zero conductance in the absence of the electric field and the strain. It is found that the external electric field can open a clear bandgap and result in an extra zero conductance. However, the strain can not induce a bandgap, which only slightly change the energy band. Correspondingly, the strain has little effect on the system's conductance. The transport behavior of zero conductance is elucidated in terms of band structures of the silicene constriction. Therefore, one can realize an effective modulation of the valley-dependent transport of the silicene constriction by combining the potential energy and the electric field. The electrical modulation of the valley polarization and zero conductance can be exploited for silicene-based valleytronics devices.