Disentanglement of the electronic and lattice parts of the order parameter in a 1D Charge Density Wave system probed by femtosecond spectroscopy

TL;DR

This study uses femtosecond spectroscopy to analyze how electronic and lattice components of the order parameter in a 1D charge density wave system behave with temperature, revealing their coupling and damping characteristics.

Contribution

It demonstrates the disentanglement of electronic and lattice parts of the order parameter in a 1D CDW system using time-resolved spectroscopy and Ginzburg-Landau theory.

Findings

Electronic part couples linearly to 2kF phonons.

CDW amplitude mode is overdamped.

Temperature affects mode amplitudes, frequencies, and damping.

Abstract

We report on the high resolution studies of the temperature (T) dependence of the q=0 phonon spectrum in the quasi one-dimensional charge density wave (CDW) compound K0.3MoO3 utilizing time-resolved optical spectroscopy. Numerous modes that appear below Tc show pronounced T-dependences of their amplitudes, frequencies and dampings. Utilizing the time-dependent Ginzburg-Landau theory we show that these modes result from linear coupling of the electronic part of the order parameter to the 2kF phonons, while the (electronic) CDW amplitude mode is overdamped.