Magneto-tunnelling spectroscopy of chiral two-dimensional electron systems

TL;DR

This paper provides a theoretical analysis of momentum-resolved tunneling in 2D electron systems with spin-orbit coupling, highlighting how spin structure influences tunneling conductance and enabling electronic characterization of materials.

Contribution

It introduces a theoretical framework for understanding magneto-tunneling in chiral 2D systems, revealing how spin-momentum coupling affects tunneling behavior and measurement techniques.

Findings

Resonant tunneling conductance is strongly affected by spin structure.

Magneto-tunneling can be used to measure pseudo-spin configurations.

The approach enables electronic characterization of barrier materials.

Abstract

We present a theoretical study of momentum-resolved tunneling between parallel two-dimensional conductors whose charge carriers have a (pseudo-)spin-1/2 degree of freedom that is strongly coupled to their linear orbital momentum. Specific examples are single and bilayer graphene as well as single-layer molybdenum disulphide. Resonant behavior of the differential tunneling conductance exhibited as a function of an in-plane magnetic field and bias voltage is found to be strongly affected by the (pseudo-)spin structure of the tunneling matrix. We discuss ramifications for the direct measurement of electronic properties such as Fermi surfaces and the dispersion curves. Furthermore, using a graphene double-layer structure as an example, we show how magneto-tunneling transport can be used to measure the pseudo-spin structure of tunnel matrix elements, thus enabling electronic characterization of the barrier material.