Pseudo magnetic field in strained graphene: revisited

TL;DR

This paper revisits the theory of strain-induced pseudo magnetic fields in graphene using a tight-binding approach, providing a generalized expression, a new effective Hamiltonian, and analyzing the validity range of previous models.

Contribution

It introduces a systematic expansion for the pseudo magnetic field, proposes a novel effective Hamiltonian, and clarifies the strain range where previous models are valid.

Findings

Pseudo magnetic field expression is valid up to 15% strain.

No K-dependent pseudo-magnetic field found.

Comparison shows previous models are accurate within certain strain limits.

Abstract

We revisit the theory of the pseudo magnetic field as induced by strain in graphene using the tight-binding approach. A systematic expansion of the hopping parameter and the deformation of the lattice vectors is presented from which we obtain an expression for the pseudo magnetic field for low energy electrons. We generalize and discuss previous results and propose a novel effective Hamiltonian. The contributions of the different terms to the pseudo magnetic field expression is investigated for a model triaxial strain profile and are compared with the full solution. Our work suggests that the previous proposed pseudo magnetic field expression is valid up to reasonably high strain 15 % and there is no K-dependent pseudo-magnetic field.