Limitations of Debye-Waller lattice temperature extraction under electronic excitation

TL;DR

Ultrafast diffraction techniques for atomic temperature measurement face limitations due to sensitivity to Debye temperature changes, which can cause inaccuracies if neglected during electronic excitation analysis.

Contribution

This work highlights the importance of accounting for Debye temperature evolution in ultrafast diffraction analysis to accurately determine atomic temperatures.

Findings

Neglecting Debye temperature changes leads to significant deviations in atomic temperature estimates.

Sensitivity of Debye-Waller analysis affects the accuracy of electron-phonon coupling measurements.

Careful evaluation of Debye temperature evolution is crucial for reliable ultrafast diffraction results.

Abstract

Ultrafast diffraction is the cutting-edge technique to extract the atomic temperature at femtosecond timescales, and further related quantities - in particular, electron-phonon coupling strength at elevated electronic temperatures. The present work demonstrates limitations of such an analysis, emphasizing the importance of careful evaluation of the evolution of the Debye temperature. It is shown that, due to the sensitivity of the Debye-Waller analysis to this parameter, neglecting its changes under electronic excitation may lead to significant deviations of the atomic temperature extracted from its true values.