Phase space analysis of quantum transport in electronic nanodevices

TL;DR

This paper introduces the Husimi function as a phase space tool to analyze quantum transport in graphene nanodevices, providing new insights into phenomena like Klein tunneling and intervalley scattering beyond traditional scattering matrix methods.

Contribution

It demonstrates the application of the Husimi function to graphene nanodevices, revealing detailed transport mechanisms and novel results on Klein tunneling and intervalley scattering.

Findings

Husimi function links scattering matrix to semiclassical transport description

Klein tunneling observed outside the Dirac regime

Intervalley scattering characterized at pn-junctions and tilted edges

Abstract

Electronic transport in nanodevices is commonly studied theoretically and numerically within the Landauer-B\"uttiker formalism: a device is characterized by its scattering properties to and from reservoirs connected by perfect semi-infinite leads, and transport quantities are derived from the scattering matrix. In some respects, however, the device becomes a "black box" as one only analyses what goes in and out. Here we use the Husimi function as a complementary tool for quantitatively understanding transport in graphene nanodevices. It is a phase space representation of the scattering wavefunctions that allows to link the scattering matrix to a more semiclassical and intuitive description and gain additional insight in to the transport process. In this article we use the Husimi function to analyze some of the fascinating electronic transport properties of graphene, \emph{Klein tunneling} and \emph{intervalley scattering}, in two exemplary graphene nanodevices. By this we demonstrate the usefulness of the Husimi function in electronic nanodevices and present novel results e.g. on Klein tunneling outside the Dirac regime and intervalley scattering at a pn-junction and a tilted graphene edge.