Theory of resonant tunneling in bilayer-graphene/hexagonal-boron-nitride heterostructures

TL;DR

This paper develops a theoretical model for vertical tunneling current in bilayer-graphene/hBN heterostructures, explaining resonant tunneling and negative differential resistance observed experimentally, based on electrostatic and electronic properties.

Contribution

It introduces a new theoretical framework for tunneling in bilayer graphene/hBN heterostructures, neglecting many-body effects, and compares results with experimental data and monolayer graphene structures.

Findings

Resonant tunneling and negative differential resistance explained by band gap and density of states.

The theory matches experimental current-voltage characteristics.

Comparison with monolayer graphene heterostructures highlights differences in tunneling behavior.

Abstract

A theory is developed for calculating vertical tunneling current between two sheets of bilayer graphene separated by a thin, insulating layer of hexagonal boron nitride, neglecting many-body effects. Results are presented using physical parameters that enable comparison of the theory with recently reported experimental results. Observed resonant tunneling and negative differential resistance in the current-voltage characteristics are explained in terms of the electrostatically-induced band gap, gate voltage modulation, density of states near the band edge, and resonances with the upper sub-band. These observations are compared to ones from similar heterostructures formed with monolayer graphene.