We investigate phonon lifetimes in VO2 single crystals. We do so in the metallic state above the metal-insulator transition (MIT), where strong structural fluctuations are known to take place. By combining inelastic X-ray scattering and Raman spectroscopy, we track the temperature dependence of several acoustic and optical phonon modes up to 1000 K. Contrary to what is commonly observed, we find that phonon lifetimes decrease with decreasing temperature. Our results show that pre-transitional fluctuations in the metallic state give rise to strong electron-phonon scattering that onsets hundreds of degrees above the transition and increases as the MIT is approached. Notably, this effect is not limited to specific points of reciprocal space that could be associated with the structural transition.
@article{arxiv.2310.20337,
title = {Anomalous T-dependence of phonon lifetimes in metallic VO2},
author = {Carl Willem Rischau and Artem Korshunov and Volodymyr Multian and Sara A. Lopez-Paz and Chubin Huang and Lucia Varbaro and Jérémie Teyssier and Yoav Kalcheim and Stefano Gariglio and Alexei Bossak and Jean-Marc Triscone and Javier del Valle},
journal= {arXiv preprint arXiv:2310.20337},
year = {2023}
}