Single-parameter pumping in graphene

TL;DR

This paper introduces a novel quantum pump mechanism in graphene leveraging its unique properties, resulting in a robust, broad-energy nonequilibrium current, with potential applications in electronic devices.

Contribution

It presents a new graphene-based quantum pump mechanism utilizing evanescent modes, with analytical and numerical analysis demonstrating its robustness and broad energy operation.

Findings

Large nonequilibrium current induced by evanescent modes

Robust pump mechanism with simple parameter dependence

Numerical and analytical validation of the effect

Abstract

We propose a quantum pump mechanism based on the particular properties of graphene, namely chirality and bipolarity. The underlying physics is the excitation of evanescent modes entering a potential barrier from one lead, while those from the other lead do not reach the driving region. This induces a large nonequilibrium current with electrons stemming from a broad range of energies, in contrast to the narrow resonances that govern the corresponding effect in semiconductor heterostructures. Moreover, the pump mechanism in graphene turns out to be robust, with a simple parameter dependence, which is beneficial for applications. Numerical results from a Floquet scattering formalism are complemented with analytical solutions for small to moderate driving.