Gate control of lattice-pseudospin currents in graphene on WS2: Effect of sublattice symmetry breaking and spin-orbit interaction

TL;DR

This paper demonstrates how gate voltage can precisely control lattice-pseudospin currents in graphene on WS2 by leveraging spin-orbit interaction and sublattice symmetry breaking, paving the way for pseudospintronics applications.

Contribution

It introduces a method to control lattice-pseudospin polarization in graphene via gate voltage, highlighting the interplay of SOI and SSB effects in a novel junction configuration.

Findings

Lattice-pseudospin polarization can be tuned from +100% to -100% with gate voltage.

Graphene on WS2 exhibits controllable pseudospin currents due to SOI and SSB effects.

L-PSP characteristics can be used to measure SOI and SSB gaps in graphene.

Abstract

Strong spin-orbit interaction (SOI) in graphene grown on tungsten disulfide (WS2) has been recently observed, leading to energy gap opening by SOI. Energy gap in graphene may also be induced by sublattice symmetry breaking (SSB) where energy level in A-sublattice is not equal to that in B-sublattice. SSB-gap may be produced by growing graphene on hexagonal boron nitride or silicon carbide. In this work, we investigate transport property in a SOI/SSB/SOI gapped graphene junction, focusing the effect of interplay of SOI and SSB. We find that, lattice-pseudospin polarization (L-PSP) can be controlled perfectly from +100% to -100% by gate voltage. This is due to the fact that in graphene grown on WS2, the carriers carry lattice-pseudo spin degree of freedom "up and down". The SSB-gapped graphene exhibits pseudo-ferromagnetism to play the role of lattice-pseudospin filtering barrier. It is also found that the SOI and SSB-gaps in graphene may be measured by characteristic of L-PSP in the junction. The proposed controllable-lattice-pseudospin currents may be applicable for graphene-based pseudospintronics.