Coherent Interlayer Tunneling and Negative Differential Resistance with High Current Density in Double Bilayer Graphene-WSe2 Heterostructures

TL;DR

This study demonstrates gate-tunable resonant tunneling and negative differential resistance in double bilayer graphene-WSe2 heterostructures, achieving high current densities and sharp resonances at room temperature and low temperature.

Contribution

It provides the first detailed experimental and theoretical analysis of coherent interlayer tunneling in aligned bilayer graphene-WSe2 heterostructures with high current densities.

Findings

High interlayer current densities of 2-2.5 μA/μm² at room temperature and 1.5 K.

Resonant tunneling peaks with ratios up to 6.

Excellent agreement between theory and experiment indicating momentum-conserving tunneling.

Abstract

We demonstrate gate-tunable resonant tunneling and negative differential resistance between two rotationally aligned bilayer graphene sheets separated by bilayer WSe2. We observe large interlayer current densities of 2 uA/um2 and 2.5 uA/um2, and peak-to-valley ratios approaching 4 and 6 at room temperature and 1.5 K, respectively, values that are comparable to epitaxially grown resonant tunneling heterostructures. An excellent agreement between theoretical calculations using a Lorentzian spectral function for the two-dimensional (2D) quasiparticle states, and the experimental data indicates that the interlayer current stems primarily from energy and in-plane momentum conserving 2D-2D tunneling, with minimal contributions from inelastic or non-momentum-conserving tunneling. We demonstrate narrow tunneling resonances with intrinsic half-widths of 4 and 6 meV at 1.5 K and 300 K, respectively.