Temperature evolution of infrared- and Raman-active phonons in graphite

TL;DR

This study investigates how the frequencies and linewidths of specific infrared- and Raman-active phonons in graphite change with temperature up to 700 K, combining experimental spectroscopy and ab initio calculations.

Contribution

It provides a comparative analysis of temperature effects on phonons in graphite using both experimental data and theoretical ab initio calculations, revealing mode-specific behaviors.

Findings

IR-active E1u mode frequency shift is nearly twice that of the Raman E2g mode.

Ab initio calculations match experimental results closely.

Different temperature dependencies observed despite similar phonon character.

Abstract

We perform a comparative experimental and theoretical study of the temperature dependence up to 700 K of the frequency and linewidths of the graphite E1u and E2g optical phonons (~1590 and 1580 cm-1) by infra-red (IR) and Raman spectroscopy. Despite their similar character, the temperature dependence of the two modes is quite different, being, e.g., the frequency shift of the IR-active E1u mode is almost twice as big as that of the Raman active E2g mode. Ab initio calculations of the anharmonic properties are in remarkable agreement with measurements and explain the observed behavior.