A many-body GW+BSE investigation of electronic and optical properties of C2N

TL;DR

This study uses advanced many-body perturbation theory to analyze the electronic and optical properties of C2N, revealing significant quasiparticle corrections, strong excitonic effects, and potential for solar energy applications.

Contribution

It provides the first comprehensive GW+BSE analysis of C2N, highlighting its excitonic effects and optical properties across different layers.

Findings

GW quasiparticle corrections exceed 0.9 eV

Exciton binding energies are over 0.6 eV in few-layer C2N

C2N exhibits broad optical absorption in visible light

Abstract

A newly synthesized layered material C2N was investigated based on many- body perturbation theory using GW plus Bethe-Salpeter equation approach. The electronic band gap was determined to be ranging from 3.75 to 1.89 eV from monolayer to bulk. Significant GW quasiparticle corrections, of more than 0.9 eV, to the Kohn-Sham band gaps from the local density approximation (LDA) calculations are found. Strong excitonic effects play a crucial role in optical properties. We found large binding energies of greater than 0.6 eV for bound excitons in few-layer C2N, while it is only 0.04 eV in bulk C2N. All the structures exhibit strong and broad optical absorption in the visible light region, which makes C2N a promising candidate for solar energy conversion, such as photocatalytic water splitting.