Optical Properties of Monolayer Bismuthene in Electric Fields

TL;DR

This paper investigates how electric fields influence the optical absorption spectra of monolayer bismuthene, revealing unique electronic properties and dramatic spectral changes under external electric fields.

Contribution

It provides a detailed analysis of the electric field effects on optical excitations and absorption features of monolayer bismuthene, highlighting its distinct electronic behavior from graphene.

Findings

Absorption spectra are significantly altered by electric fields.

Threshold frequency becomes zero at a critical electric field.

Distinct absorption peaks relate to band-edge states and constant-energy loops.

Abstract

Optical excitations of monolayer bismuthene present the rich and unique absorption spectra. The threshold frequency is not equal to an indirect energy gap, and it becomes zero under the critical electric field. The frequency, number, intensity and form of the absorption structures are dramatically changed by the external field. The prominent peaks and the observable shoulders, respectively, arise from the constant-energy loop and the band-edge states of parabolic dispersions. These directly reflect the unusual electronic properties, being very different from those in monolayer graphene.