Current resonances in graphene with time dependent potential barriers

TL;DR

This paper develops a method to analyze electron transport in graphene with time-dependent potential barriers, revealing resonant effects and unexpected current components.

Contribution

It introduces a novel approach to solve the Dirac-Weyl equation with arbitrary time-dependent potentials in graphene.

Findings

Resonant enhancement of backscattering and currents predicted.

Resonance conditions resemble Shapiro-steps in Josephson junctions.

Non-zero y-current component observed for zero y-momentum carriers.

Abstract

A method is derived to solve the massless Dirac-Weyl equation describing electron transport in a mono-layer of graphene with a scalar potential barrier U(x,t), homogeneous in the y-direction, of arbitrary x- and time dependence. Resonant enhancement of both electron backscattering and currents, across and along the barrier, is predicted when the modulation frequencies satisfy certain resonance conditions. These conditions resemble those for Shapiro-steps of driven Josephson junctions. Surprisingly, we find a non-zero y-component of the current for carriers of zero momentum along the y-axis.