Quantum vibronic effects on the electronic properties of solid and molecular carbon

TL;DR

This paper investigates quantum vibronic effects on the electronic properties of carbon materials using an advanced simulation method, revealing significant electron-phonon interactions and their impact on band gaps in amorphous and crystalline carbon.

Contribution

It introduces a combined path integral FPMD approach with a colored noise thermostat to accurately model quantum vibronic effects in large carbon systems.

Findings

Quantum vibronic coupling significantly affects the electronic properties of carbon allotropes.

The zero-phonon band gap renormalization in diamond is larger than previously estimated.

The method is computationally efficient for large supercells, including amorphous solids.

Abstract

We study the effect of quantum vibronic coupling on the electronic properties of carbon allotropes, including molecules and solids, by combining path integral first principles molecular dynamics (FPMD) with a colored noise thermostat. In addition to avoiding several approximations commonly adopted in calculations of electron-phonon coupling, our approach only adds a moderate computational cost to FPMD simulations and hence it is applicable to large supercells, such as those required to describe amorphous solids. We predict the effect of electron-phonon coupling on the fundamental gap of amorphous carbon, and we show that in diamond the zero-phonon renormalization of the band gap is larger than previously reported.