Fermionic symmetry-protected topological state in strained graphene

TL;DR

This paper explores how strained graphene under combined real and pseudo magnetic fields can host a novel fermionic symmetry-protected topological state, expanding the understanding of topological phases in graphene with artificial gauge fields.

Contribution

It proposes a new topological state in graphene induced by strain and magnetic fields, characterized through theoretical models and numerical analysis.

Findings

Identification of a specific field ratio for topological state realization

Model wave functions and Chern-Simons theory characterize the state

Potential for new topological phases in strained graphene with gauge fields

Abstract

The low-energy physics of graphene is described by relativistic Dirac fermions with spin and valley degrees of freedom. Mechanical strain can be used to create a pseudo magnetic field pointing to opposite directions in the two valleys. We study interacting electrons in graphene exposed to both an external real magnetic field and a strain-induced pseudo magnetic field. For a certain ratio between these two fields, it is proposed that a fermionic symmetry-protected topological state can be realized. The state is characterized in detail using model wave functions, Chern-Simons field theory, and numerical calculations. Our paper suggests that graphene with artificial gauge fields may host a rich set of topological states.