Berlin 2024 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 80: Correlated Electrons: Poster

TT 80.5: Poster

Donnerstag, 21. März 2024, 15:00–18:00, Poster E

Unveiling novel interactions: hybridization variations in mixed-valent TmSe under negative pressure — •Chul Hee Min^1,2, Simon Müller³, Michael Heber⁴, Lenart Dudy⁵, Woojae Choi⁶, Yong Seung Kwon⁶, Hendrik Bentmann¹, Friedrich Reinert², and Kai Rossnagel^2,4 — ¹FYI, NTNU, Norway — ²IEAP, CAU Kiel, Germany — ³EP7, Uni. Würzburg, Germany — ⁴DESY, Germany — ⁵SOLEIL, France — ⁶DGIST, South Korea

In the 1980s, a range of interactions associated with the localized 4f states in rare earth compounds were contemplated, but the extent of their influence on physical properties remained unclear. Consequently, in most instances, these interactions were overlooked, and the standard Anderson model was commonly employed for such compounds. However, our recent investigations have uncovered spectroscopic evidence of a hitherto unrecognized interaction in the mixed-valent TmSe, particularly when subjected to negative pressure (the substitution of Se with Te). Our photoemission results reveal a distinct behavior: the 4f peak, previously considered singular, actually comprises two peaks that progressively separate with increasing the lattice parameter. Moreover, we demonstrate a correlated variation in the hybridization between the 4f states and other states. Consequently, our findings highlight a variable interaction that evolves with lattice expansion, with the bonding character transitioning from 5d to the cation p states. This discovery underscores the necessity of incorporating at least one additional hybridization into the Anderson model to effectively capture the mixed-valent characteristics.

Keywords: photoemission; mixed valence; rare earth compounds