Dephasing of G-Band Phonons in Single-Wall Carbon Nanotubes Probed via Impulsive Stimulated Raman Scattering

TL;DR

This study investigates the coherent dynamics and dephasing mechanisms of G-band phonons in single-walled carbon nanotubes using impulsive stimulated Raman scattering, revealing temperature-dependent dephasing influenced by interactions with radial breathing modes.

Contribution

It provides a detailed model explaining phonon amplitude dependence on probe energy and chirped pulses, and links phonon dephasing to anharmonic interactions with radial breathing modes.

Findings

Phonon amplitude varies with probe energy and excitation chirp.

Dephasing rate increases with temperature, showing thermally-activated behavior.

Dephasing energy matches the radial breathing mode frequency.

Abstract

We have studied the coherent dynamics of G-band phonons in single-walled carbon nanotubes through impulsive stimulated Stokes and anti-Stokes Raman scattering. The probe energy dependence of phonon amplitude as well as preferential occurrence between Stokes and anti-Stokes components in response to chirped-pulse excitation are well explained within our model. The temperature dependence of the observed dephasing rate clearly exhibits a thermally-activated component, with an activation energy that coincides with the frequency of the radial breathing mode (RBM). This fact provides a clear picture for the dephasing of optical phonons by random frequency modulation via interaction with the RBM through anharmonicity.