Scalable tight-binding model for strained graphene

TL;DR

This paper extends a scalable tight-binding model for graphene to include elastic strain, enabling efficient quantum transport simulations in large-scale strained graphene devices by scaling displacement fields appropriately.

Contribution

The authors generalize the scalable tight-binding model for graphene to account for elastic strain, maintaining invariance of the long-wavelength theory through specific scaling of displacement fields.

Findings

Validated scaling laws through numerical simulations of pseudomagnetic fields and local density of states.

Demonstrated the model's capability to simulate pseudo-Landau levels and hybrid Landau levels.

Applied the model to simulate quantum transport in a strained graphene device with a uniaxial strain barrier.

Abstract

We generalize the scalable tight-binding model for graphene, which allows for efficient quantum transport simulations in the Dirac regime, to account for elastic strain. We show that the original scalable model with scaling factor $s$ is readily applicable to strained graphene, provided that the displacement fields corresponding to the deformed graphene lattice are properly scaled. In particular, we show that the long-wavelength theory remains invariant when the strain tensor is scaled by $s$. This is achieved in practice by scaling the in-plane displacement fields by $s$ while the out-of-plane displacements have to be scaled by $\sqrt{s}$. We confirm these scaling laws by extensive numerical simulations, starting with the pseudomagnetic field and the local density of states for different scaled lattices. The latter allows us to study pseudo-Landau levels as well as hybrid Landau levels in the presence of an external magnetic field. Finally, we consider quantum transport simulations motivated by a recent experiment, where a uniaxial strain barrier is engineered in monolayer graphene by vertically misaligned gates. Our work generalizes the scalable tight-binding model to allow for efficient modeling of quantum transport in large-scale strained graphene devices.