Unified understanding of the valence transition in the rare-earth monochalcogenides under pressure

Abstract

Valence instability is a key ingredient of the unusual properties of f electron materials, yet a clear understanding is lacking as it involves a complex interplay between f electrons and conduc- tion states. Here we propose a unified picture of pressure-induced valence transition in Sm and Yb monochalcogenides, considered as model system for mixed valent 4f-electron materials. Using high-resolution x-ray absorption spectroscopy, we show that the valence transition is driven by the promotion of a 4f electron specifically into the lowest unoccupied (LU) 5d t2g band. We demonstrate with a promotional model that the nature of the transition at low pressures is intimately related to the density of states of the LU band, while at high pressures it is governed by the hybridization strength. These results set a new standard for the generic understanding of valence fluctuations in f-electron materials.

References in corpus (2)

• Valence Instability and Superconductivity in Heavy Fermion Systems
• Reentrant valence transition in EuO at high pressures: beyond the bond-valence model

Cited by in corpus (10)

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• Electronic correlations of element cerium under high pressure
• Pressure-Driven Topological Phase Transition in the Yb Chalcogenides YbO and YbS
• Exploring itinerant states in divalent hexaborides using rare-earth $L$ edge resonant inelastic X-ray scattering
• Current-Induced Metallization and Valence Transition in Black SmS
• Survival of the metallic state in a single-hole multiband $p$-orbital molecular system