Gate driven adiabatic quantum pumping in graphene

TL;DR

This paper introduces a graphene-based quantum pump driven by oscillating voltages, highlighting its robustness, ability to utilize evanescent modes, and universal response at the Dirac point, advancing quantum transport understanding.

Contribution

It presents a novel graphene quantum pump design that leverages evanescent modes and demonstrates universal behavior at the Dirac point under weak driving conditions.

Findings

Graphene pumps are more robust against thermal effects.

Evanescent modes dominate pumping at the Dirac point.

Universal response observed under weak driving conditions.

Abstract

We propose a new type of quantum pump made out of graphene, adiabatically driven by oscillating voltages applied to two back gates. From a practical point of view, graphene-based quantum pumps present advantages as compared to normal pumps, like enhanced robustness against thermal effects and a wider adiabatic range in driving frequency. From a fundamental point of view, apart from conventional pumping through propagating modes, graphene pumps can tap into evanescent modes, which penetrate deeply into the device as a consequence of chirality. At the Dirac point the evanescent modes dominate pumping and give rise to a universal response under weak driving for short and wide pumps, even though the charge per unit cycle in not quantized.