Electronic structure of graphene-nanoribbons on hexagonal boron nitride

TL;DR

This study investigates how hexagonal boron nitride substrates influence the electronic properties of graphene nanoribbons, revealing significant spin-splitting effects, especially in zigzag configurations, which are promising for quantum applications.

Contribution

It provides new insights into substrate-induced electronic modifications in graphene nanoribbons, highlighting potential for spintronic and quantum device engineering.

Findings

Boron nitride can significantly alter the electronic structure of graphene nanoribbons.

Strong spin-splitting (up to 40 meV) occurs in zigzag nanoribbons due to substrate effects.

Stacking configurations critically influence the extent of electronic modifications.

Abstract

Hexagonal boron nitride is an ideal dielectric to form two-dimensional heterostructures due to the fact that it can be exfoliated to be just few atoms thick and its a very low density of defects. By placing graphene nanoribbons on high quality hexagonal boron nitride it is possible to create ideal quasi one dimensional (1D) systems with very high mobility. The availability of high quality one-dimensional electronic systems is of great interest also given that when in proximity to a superconductor they can be effectively engineered to realize Majorana bound states. In this work we study how a boron nitride substrate affects the electronic properties of graphene nanoribbons. We consider both armchair and zigzag nanoribbons. Our results show that for some stacking configurations the boron nitride can significantly affect the electronic structure of the ribbons. In particular, for zigzag nanoribbons, due to the lock between spin and sublattice degree of freedom at the edges, the hexagonal boron nitride can induce a very strong spin-splitting of the spin polarized, edge sates. We find that such spin-splitting can be as high as 40~meV.