Hao Tjeng – Max Planck
Title: Stabilization of U 5f2 configuration in UTe2 through U 6d dimers in the presence of Te2 chains

Abstract: We investigate the topological superconductor candidate UTe2 using high-resolution valence-band resonant inelastic x-ray scattering at the U M4,5-edges. We observe atomic-like low-energy excitations that support the correlated nature of this unconventional superconductor. These excitations originate from the U 5f2 configuration, which is unexpected since the short Te2-Te2 distances exclude Te2 being 2-. By utilizing the photoionization cross-section dependence of the photoemission spectra in combination with band structure calculations, we infer that the stabilization of the U 5f2 configuration is due to the U 6d bonding states in the U-dimers acting as a charge reservoir. Our results emphasize that the description of the physical properties should commence with a 5f2 ansatz.

Speaker Bio: Prof. Tjeng has been Director and Scientifc member at the Max Planck Institute for Chemical Physics of Solids since October 2009. He is an experimental physicist and has previously been associated with the Royal Netherlands Academy of Sciences, the Solid State Physics Laboratory, University of Groningen, The Netherlands, and the University of Cologne, Germany.