Phonons of graphene and graphitic materials derived from the empirical potential LCBOPII

TL;DR

This paper calculates phonon dispersions of graphene and graphite using the LCBOPII empirical potential, showing good agreement with experiments and exploring temperature effects and multilayer splitting for material characterization.

Contribution

It introduces phonon calculations based on the LCBOPII potential, highlighting its accuracy and discussing temperature-dependent properties and multilayer phonon mode splitting.

Findings

Good agreement with experimental phonon dispersions

Bending rigidity of graphene is 0.69 eV at zero temperature

Flexural mode splitting can be used for multilayer characterization

Abstract

We present the interatomic force constants and phonon dispersions of graphite and graphene from the LCBOPII empirical bond order potential. We find a good agreement with experimental results, particularly in comparison to other bond order potentials. From the flexural mode we determine the bending rigidity of graphene to be 0.69 eV at zero temperature. We discuss the large increase of this constant with temperature and argue that derivation of force constants from experimental values should take this feature into account. We examine also other graphitic systems, including multilayer graphene for which we show that the splitting of the flexural mode can provide a tool for characterization.