Gate-Tunable Resonant Tunneling in Double Bilayer Graphene Heterostructures

TL;DR

This paper reports the observation of gate-tunable resonant tunneling and negative differential resistance in double bilayer graphene heterostructures, with analysis of band alignment and factors affecting resonance characteristics.

Contribution

It introduces a method to achieve and analyze gate-tunable resonant tunneling in double bilayer graphene heterostructures separated by hBN.

Findings

Resonance occurs when bilayer graphene energy bands align.

Tunneling resistance depends on hBN thickness.

Resonance width is influenced by mobility and rotational alignment.

Abstract

We demonstrate gate-tunable resonant tunneling and negative differential resistance in the interlayer current-voltage characteristics of rotationally aligned double bilayer graphene heterostructures separated by hexagonal boron-nitride (hBN) dielectric. An analysis of the heterostructure band alignment using individual layer densities, along with experimentally determined layer chemical potentials indicates that the resonance occurs when the energy bands of the two bilayer graphene are aligned. We discuss the tunneling resistance dependence on the interlayer hBN thickness, as well as the resonance width dependence on mobility and rotational alignment.