Local Optical Conductivity of Bilayer Graphene with Kink Potential

TL;DR

This paper investigates how localized chiral states at a domain wall in bilayer graphene influence its local optical conductivity, revealing detectable spectroscopic signatures and insights into the band structure.

Contribution

It provides a detailed analysis of the local optical response of bilayer graphene with a kink potential, highlighting the role of domain wall states and their spectroscopic signatures.

Findings

Chiral states significantly affect local optical conductivity.

Spectroscopic features can reveal energy separation of chiral states.

Spatial distribution of conductivity informs about bound and topological states.

Abstract

We study the optical response of bilayer graphene with a kink potential composed of a domain wall separating two AB regions with opposite interlayer bias. The band structure and the local optical conductivity in real space are investigated in details based on a continuum model. We find that the one-dimensional chiral states localized at the domain wall contribute significantly to the local optical conductivity, which shows a clear distinction in different regions. The effects of domain wall states on optical conductivity can be detected by spatially and frequency resolved spectroscopic features. From the spectrum at various Fermi energies, important features in the band structure such as the energy separation between two chiral states can be directly measured. When the domain wall region is broad, the spatial distribution of local optical conductivity can provide important information on the bound states as well as the topological domain wall states.