Excitonic Effects on Optical Absorption Spectra of Doped Graphene

TL;DR

This study uses first-principles calculations to analyze how doping affects the optical absorption spectra of graphene, revealing that excitonic effects and self-energy corrections nearly cancel each other, with notable absorbance increases in the infrared and visible ranges.

Contribution

It provides a detailed first-principles analysis of excitonic effects in doped graphene, highlighting the interplay between self-energy corrections and electron-hole interactions.

Findings

Self-energy corrections and excitonic effects nearly cancel each other.

Optical absorption peak remains around 4.5 eV regardless of doping.

Enhanced absorbance observed in the infrared and visible-light regime.

Abstract

We have performed first-principles calculations to study optical absorption spectra of doped graphene with many-electron effects included. Both self-energy corrections and electron-hole interactions are reduced due to the enhanced screening in doped graphene. However, self-energy corrections and excitonic effects nearly cancel each other, making the prominent optical absorption peak fixed around 4.5 eV under different doping conditions. On the other hand, an unexpected increase of the optical absorbance is observed within the infrared and visible-light frequency regime (1 ~ 3 eV). Our analysis shows that a combining effect from the band filling and electron-hole interactions results in such an enhanced excitonic effect on the optical absorption. These unique variations of the optical absorption of doped graphene are of importance to understand relevant experiments and design optoelectronic applications.