Quantum charge pumping in graphene-based devices: When lattice defects do help

TL;DR

This paper demonstrates that in graphene nanoribbons, the presence of lattice defects can significantly enhance quantum charge pumping efficiency, with even a single defect increasing pumped charge by two orders of magnitude.

Contribution

It reveals the counterintuitive role of defects in boosting quantum charge pumping in graphene, using atomistic simulations to show defect-induced enhancements.

Findings

Single defects can increase pumped charge by two orders of magnitude.

Defects play a crucial role in adiabatic quantum pumping in graphene.

Atomistic simulations confirm defect-induced charge enhancement.

Abstract

Quantum charge pumping, the quantum coherent generation of a dc current at zero bias through time dependent potentials, provides outstanding opportunities for metrology and the development of new devices. The long electronic coherence times and high quality of the crystal structure of graphene may provide suitable building blocks for such quantum pumps. Here, we focus in adiabatic quantum pumping through graphene nanoribbons in the Fabry-P\'{e}rot regime highlighting the crucial role of defects by using atomistic simulations. We show that even a single defect added to the pristine structure may produce a two orders of magnitude increase in the pumped charge.