Strong anisotropic optical properties of 8-Pmmn borophene: a many-body perturbation study

TL;DR

This study uses advanced many-body perturbation theory to analyze the anisotropic optical properties of 8-Pmmn borophene, revealing strong polarization-dependent absorption and excitonic effects.

Contribution

It provides the first detailed theoretical analysis of 8-Pmmn borophene's optical anisotropy using GW and Bethe-Salpeter methods.

Findings

Strong optical absorbance anisotropy predicted.

Electron-hole interactions cause a redshift in absorption peaks.

Anisotropic excitonic wave functions are identified.

Abstract

Using first-principle many-body perturbation theory, we investigate the optical properties of 8- borophene at two levels of approximations; the GW method considering only the electron-electron interaction and the GW in combination with the Bethe-Salpeter equation including electron-hole coupling. The band structure exhibits anisotropic Dirac cones with semimetallic character. The optical absorption spectra are obtained for different light polarizations and we predict strong optical absorbance anisotropy. The absorption peaks undergo a global redshift when the electron-hole interaction is taken into account due to the formation of bound excitons which have an anisotropic excitonic wave function.