Electronic structure of spontaneously strained graphene on hexagonal Boron Nitride

TL;DR

This paper develops a low-energy model to analyze how spontaneous strains in graphene on hexagonal Boron Nitride alter its electronic band structure, gap, and topological properties, providing insights into strain-induced effects.

Contribution

It introduces a simple theoretical model incorporating spontaneous strains, pseudogauge fields, and deformation potentials to explain electronic modifications in aligned graphene on hBN.

Findings

Spontaneous strains significantly modify graphene's electronic structure.

A bandgap opens at the Dirac point due to lattice distortions.

The model characterizes changes in density of states and band topology.

Abstract

Hexagonal Boron Nitride substrates have been shown to dramatically improve the electric properties of graphene. Recently, it has been observed that when the two honeycomb crystals are close to perfect alignment, strong lattice distortions develop in graphene due to the moir\'e adhesion landscape. Simultaneously a gap opens at the Dirac point. Here we derive a simple low energy model for graphene carriers close to alignment with the substrate, taking into account spontaneous strains at equilibrium, pseudogauge fields and deformation potentials. We carry out a detailed characterisation of the modified band structure, gap, local and global density of states, and band topology in terms of physical parameters. We show that the overall electronic structure is strongly modified by the spontaneous strains.