Efficient charge pumping in graphene

TL;DR

This paper demonstrates that a graphene quantum pump driven by vibrating potential barriers can generate highly efficient charge pumping, especially near the Dirac point, with oscillatory behavior influenced by carrier concentration.

Contribution

It introduces a novel graphene quantum pump design that leverages evanescent modes for enhanced charge pumping efficiency at the Dirac point.

Findings

Pumped current diverges at the Dirac point for highly doped leads.

Oscillatory pumped current increases with carrier concentration.

Graphene pump with vibrating barriers outperforms oscillating barrier designs.

Abstract

We investigate a graphene quantum pump, adiabatically driven by two thin potential barriers vibrating around their equilibrium positions. For the highly doped leads, the pumped current per mode diverges at the Dirac point due to the more efficient contribution of the evanescent modes in the pumping process. The pumped current shows an oscillatory behavior with an increasing amplitude as a function of the carrier concentration. This effect is in contrast to the decreasing oscillatory behavior of the similar normal pump. The graphene pump driven by two vibrating thin barriers operates more efficient than the graphene pump driven by two oscillating thin barriers.