Strain-controlled valley and spin separation in silicene heterojunctions

TL;DR

This study demonstrates that applying strain and electric fields to silicene heterojunctions enables control over valley and spin separation of electrons, advancing potential valleytronics applications.

Contribution

It introduces a method to modulate valley- and spin-dependent transport in silicene using combined strain and electric fields, which was not previously demonstrated.

Findings

Strain and electric field together cause valley- and spin-dependent electron separation.

Electrons of valleys K and K' are separated into opposite directions.

Up-spin and down-spin electrons are also deflected oppositely.

Abstract

We adopt the tight-binding mode-matching method to study the strain effect on silicene heterojunctions. It is found that valley- and spin-dependent separation of electrons cannot be achieved by the electric field only. When a strain and an electric field are simultaneously applied to the central scattering region, not only are the electrons of valleys K and K' separated into two distinct transmission lobes in opposite transverse directions, but the up-spin and down-spin electrons will also move in the two opposite transverse directions. Therefore, one can realize an effective modulation of valley- and spin-dependent transport by changing the amplitude and the stretch direction of the strain. The phenomenon of the strain-induced valley and spin deflection can be exploited for silicene-based valleytronics devices.