Adiabatic pumping driven by moving kink and quantum standard ampere in buckled graphene nanoribbon

TL;DR

This paper demonstrates that moving kinks in buckled graphene nanoribbons can generate highly efficient, quantized charge pumping, potentially establishing a quantum standard for the ampere based on topological electronic states.

Contribution

It introduces a numerical study showing quantized charge pumping via moving kinks in graphene, proposing a new method for quantum current standards.

Findings

Kinks induce efficient charge pumping close to the Fermi velocity limit.

Insulating ribbons exhibit quantized charge transfer of 2e per kink.

Localized electronic states move with the kink, enabling quantization.

Abstract

A quantum pump in buckled graphene ribbon with armchair edges is discussed numerically. By solving the Su-Schrieffer-Heeger model and performing the computer simulation of quantum transport we find that a kink adiabatically moving along the metallic ribbon results in highly-efficient pumping, with a charge per kink transition close to the maximal value determined by the Fermi velocity in graphene. Remarkably, insulating nanoribbon show the quantized value of a charge per kink ($2e$) in relatively wide range of the system parameters, providing a candidate for the quantum standard ampere. We attribute it to the presence of a localized electronic state, moving together with a kink, whose energy lies within the ribbon energy gap.