Ultrafast Transition from State-Blocking Dynamics to Electron Localization in Transition Metal β-Tungsten

• Published in: Physical review letters Vol. 131; no. 22; p. 226901
• Main Authors: de Vos, E W, Neb, S, Niedermayr, A, Burri, F, Hollm, M, Gallmann, L, Keller, U
• Format: Journal Article
• Language: English
• Published: United States 01-12-2023
• ISSN: 0031-9007; 1079-7114
• DOI: 10.1103/PhysRevLett.131.226901

We describe an ultrafast transition of the electronic response of optically excited transition metal β-tungsten with few-femtosecond time resolution. The response moves from a regime where state filling of the excited carrier population around the Fermi level dominates towards localization of carriers onto the outer d orbitals. This is in contrast to previous measurements using ultrafast element-specific core-level spectroscopy enabled by attosecond transient absorption spectroscopy on transition metals such as titanium and around the transition metal atom in transition metal dichalchogenides MoTe_{2} and MoSe_{2}. This surprisingly different dynamical response for β-tungsten can be explained by considering the electron-electron dynamics on a few-femtosecond timescale and the slower electron-phonon thermalization dynamics.