Journal Article

Attosecond screening dynamics mediated by electron localization in transition metals

Lucchini, M, Volkov, M, Schlaepfer, F, Gallmann, L, Rubio, A, Keller, U, Sato, S A, Kasmi, L, Hartmann, N

2019

Overview

Transition metals, with their densely confined and strongly coupled valence electrons, are key constituents of many materials with unconventional properties1, such as high-temperature superconductors, Mott insulators and transition metal dichalcogenides2. Strong interaction offers a fast and efficient lever to manipulate electron properties with light, creating promising potential for next-generation electronics3–6. However, the underlying dynamics is a hard-to-understand, fast and intricate interplay of polarization and screening effects, which are hidden below the femtosecond timescale of electronic thermalization that follows photoexcitation7. Here, we investigate the many-body electron dynamics in transition metals before thermalization sets in. We combine the sensitivity of intra-shell transitions to screening effects8 with attosecond time resolution to uncover the interplay of photo-absorption and screening. First-principles time-dependent calculations allow us to assign our experimental observations to ultrafast electronic localization on d orbitals. The latter modifies the electronic structure as well as the collective dynamic response of the system on a timescale much faster than the light-field cycle. Our results demonstrate a possibility for steering the electronic properties of solids before electron thermalization. We anticipate that our study may facilitate further investigations of electronic phase transitions, laser–metal interactions and photo-absorption in correlated-electron systems on their natural timescales.

• Publisher: Nature Publishing Group
• Subject: Absorption / Dynamic response / Electronic properties / Electronic structure / Electrons / First principles / High temperature / High temperature superconductors / Insulators / Localization / Metals / Phase transitions / Screening / Steering / Strong interactions (field theory) / Thermalization (energy absorption) / Time dependence / Transition metals