Proximity induced spin-orbit splitting in graphene nanoribbons on transition metal dichalcogenides

TL;DR

This study investigates how proximity effects from transition metal dichalcogenides influence the spin-orbit splitting in graphene nanoribbons, revealing significant effects with metallic TMDs and potential for topological superconductivity.

Contribution

It provides first-principles analysis of proximity-induced spin-orbit effects in GNRs on TMDs, highlighting the dependence on TMD type and stacking configuration.

Findings

Semiconducting TMDs induce minimal spin-splitting (~few meV) in GNRs.

Metallic TMDs like NbSe2 cause large, stacking-dependent spin-splitting (up to 40 meV).

Optimal configurations could enable topological superconducting states supporting Majorana modes.

Abstract

We study the electronic structure of heterostructures formed by a graphene nanoribbon (GNR) and a transition metal dichalcogenides (TMD) monolayer using first-principles. We consider both semiconducting TMDs and metallic TMDs, and different stacking configurations. We find that when the TMD is semiconducting the effects on the band structure of the GNRs are small. In particular the spin-splitting induced by proximity on the GNRs bands is only of the order of few meV irrespective of the stacking configuration. When the TMD is metallic, such as NbSe2, we find that the spin-splitting induced in the GNRs can be very large and strongly dependent on the stacking configuration. For optimal stacking configurations the proximity-induced spin-splitting is of the order of 20 meV for armchair graphene nanoribbons, and as high as 40 meV for zigzag graphene nanoribbons. This results are encouraging for the prospects of using GNR-TMD heterostructures to realize quasi one-dimensional topological superconducting states supporting Majorana modes.