Straintronics beyond homogeneous deformation

TL;DR

This paper develops a continuum theory of graphene that incorporates both homogeneous and non-homogeneous deformations, revealing new pseudo-gauge fields and electronic phenomena such as valley-polarized charge transport and simplified magnetic field generation.

Contribution

It introduces a unified continuum framework for graphene deformations, capturing non-homogeneous effects and predicting novel electronic behaviors beyond existing homogeneous theories.

Findings

Non-CB deformations enable long-distance valley-polarized charge transport.

Non-CB deformation obviates the need for triaxial strains to generate uniform magnetic fields.

Lattice relaxation effects in corrugations are explained by the interplay of CB and non-CB deformations.

Abstract

We present a continuum theory of graphene treating on an equal footing both homogeneous Cauchy-Born (CB) deformation, as well as the microscopic degrees of freedom associated with the two sublattices. While our theory recovers all extant results from homogeneous continuum theory, the Dirac-Weyl equation is found to be augmented by new pseudo-gauge and chiral fields fundamentally different from those that result from homogeneous deformation. We elucidate three striking electronic consequences: (i) non-CB deformations allow for the transport of valley polarized charge over arbitrarily long distances e.g. along a designed ridge; (ii) the triaxial deformations required to generate an approximately uniform magnetic field are unnecessary with non-CB deformation; and finally (iii) the vanishing of the effects of a one dimensional corrugation seen in \emph{ab-initio} calculation upon lattice relaxation are explained as a compensation of CB and non-CB deformation.