Quantum Hall response to time-dependent strain gradients in graphene

TL;DR

This paper explores how time-dependent strain gradients in graphene generate pseudoelectric fields that, combined with pseudomagnetic fields, induce a quantized Hall-like charge current, revealing novel strain-induced electronic responses.

Contribution

It introduces the concept of a pseudoelectric field in graphene due to oscillating strain and analyzes its effects on Hall response, extending the analogy with electromagnetic phenomena.

Findings

Predicts an approximately quantized Hall current induced by dynamic strain.

Shows the Hall current is robust against screening effects.

Proposes an experimental setup for observing strain-induced quantum Hall effects.

Abstract

Mechanical deformations of graphene induce a term in the Dirac Hamiltonian which is reminiscent of an electromagnetic vector potential. Strain gradients along particular lattice directions induce local pseudomagnetic fields and substantial energy gaps as indeed observed experimentally. Expanding this analogy, we propose to complement the pseudomagnetic field by a pseudoelectric field, generated by a time dependent oscillating stress applied to a graphene ribbon. The joint Hall-like response to these crossed fields results in a strain-induced charge current along the ribbon. We analyze in detail a particular experimental implementation in the (pseudo) quantum Hall regime with weak intervalley scattering. This allows us to predict an (approximately) quantized Hall current which is unaffected by screening due to diffusion currents.