Local optical conductivity of strain solitons in bilayer graphene with arbitrary soliton angle

TL;DR

This paper investigates how the local optical conductivity in bilayer graphene with domain wall solitons varies with the soliton angle, revealing tunable spectral features influenced by strain and external pressure.

Contribution

It introduces the soliton angle as a key factor affecting local optical conductivity and demonstrates its tunability via external pressure in bilayer graphene.

Findings

Resonance peaks in conductivity spectra depend on soliton angle.

External pressure can double the resonance peak energies.

Local optical conductivity shows significant spatial variation.

Abstract

We theoretically study the electronic band structure and local optical conductivity of domain wall solitons in bilayer graphene (as well as twisted bilayer graphene) with arbitrary soliton angle, which characterizes the local strain direction. We demonstrate that the soliton angle provides an important yet underexplored degree of freedom that can strongly modify the local optical conductivity. The conductivity spectrum features resonance peaks associated with interband transitions involving the topological as well as high-energy soliton states. Two most prominent peaks exhibit continuous suppression and enhancement, respectively, with the soliton angle. The dependence of the peaks on Fermi energy provides important information about the soliton band structure. The local optical conductivity exhibits substantial spatial dependence, which can be used to study the spatial distribution of the soliton states. Furthermore, we show that the conductivity spectra for all soliton angles are broadly tunable by external pressure, which can double the energies of the resonance peaks in experimentally achievable pressure ranges.