Electromechanical response at polar zigzag boundaries in hybrid monolayers

Rafael Martinez-Gordillo,Miguel Pruneda

doi:10.1103/physrevb.91.045411

Abstract

First-principles calculations are used to demonstrate electromechanical control of charge and spin at zigzag-edged interfaces between graphene and boron-nitride domains in hybrid monolayers. We show how, through a direct piezoelectric effect, the interfacial bound charges and associated electric fields can be tuned by application of an external mechanical force (stress) on the system. This results in mechanical control of the edge magnetization (piezomagnetic effect), and the possibility to transform a semiconducting heterostructure into a half-metal. The inverse effect (application of an external electric field to induce a mechanical deformation) goes together with a magnetoelectric response, which under ideal conditions we estimate to be comparable to that of prototypical ${\mathrm{Cr}}_{2}{\mathrm{O}}_{3}$. These effects originate from the magnetic properties of graphene's zigzag edges and the dielectric properties of the boron-nitride domain, and can also be expected in any other coplanar heterostructures with polar discontinuities.

Highlights

Hybrid C/BN nanostructures offer a new route to engineering electronic and optical properties of graphene-based devices
The edge states can be tuned by application of an external electric field, and, in combination with the half-metallicity in hybrid C/BN heterostructures, result in a magnetoelectric response, which we evaluate for an ideal composition and geometry to be larger than the one predicted for graphene ribbons on silicon substrates [26]
We have shown different ways to engineer the electronic properties of hybrid C/BN nanostructures by tuning the bound charge at polar zigzag interfaces

Summary

INTRODUCTION

Hybrid C/BN nanostructures offer a new route to engineering electronic and optical properties of graphene-based devices. A number of very recent experiments have observed that in these zigzag boundaries between graphene and h-BN domains, novel interfacial electronic states appear [6,7,8], confirming early theoretical predictions [9,10,11,12,13,14,15,16]. The edge states can be tuned by application of an external electric field, and, in combination with the half-metallicity in hybrid C/BN heterostructures, result in a magnetoelectric response, which we evaluate for an ideal composition and geometry to be larger than the one predicted for graphene ribbons on silicon substrates [26]

METHODOLOGY

RESPONSE TO MECHANICAL DEFORMATIONS

RESPONSE TO EXTERNAL ELECTRIC FIELDS

CONCLUSIONS