Transport and particle-hole asymmetry in graphene on boron nitride

TL;DR

This paper investigates how moiré patterns in graphene on hBN influence electronic transport, revealing a notable particle-hole asymmetry linked to the effective Hamiltonian describing the system.

Contribution

It applies a derived effective Hamiltonian to analyze transport properties and uncovers the physical origin of particle-hole asymmetry in graphene on hBN.

Findings

Transport features at specific electron/hole fillings reflect Bragg scattering strength.

A pronounced particle-hole asymmetry is observed and explained.

The effective Hamiltonian captures key physical mechanisms behind the asymmetry.

Abstract

All local electronic properties of graphene on a hexagonal boron nitride (hBN) substrate exhibit spatial moir\'e patterns related to lattice constant and orientation differences between shared triangular Bravais lattices. We apply a previously derived effective Hamiltonian for the $\pi$-bands of graphene on h-BN to address the carrier-dependence of transport properties, concentrating on the conductivity features at four electrons and four holes per unit cell. These transport features measure the strength of Bragg scattering of $\pi$-electrons off the moir\'e pattern, and exhibit a striking particle-hole asymmetry that we trace to specific features of the effective Hamiltonian that we interpret physically.