Interplay of Valence and Semimetal-to-Insulator Transitions in SmS

Abstract

Recent discoveries of a new type of quantum criticality arising from Yb-valence fluctuations in Yb-based metal in periodic crystal and quasicrystal have opened a new class of quantum critical phenomena in correlated electron systems. To clarify whether this new concept can be generalized to other rare-earth-based semimetal and insulator, we study SmS which exhibits golden-black phase transition under pressure. By constructing the model for SmS, we show that Coulomb repulsion between 4f and 5d orbitals at Sm drives first-order valence transition (FOVT) and semimetal-to-insulator transition (MIT) simultaneously, which explains the golden-black phase transition. We clarify the ground-state phase diagram for the FOVT and MIT by identifying the quantum critical point of the FOVT. We find that exciton condensates in both semimetal and insulator phases. Our result explains measured peak anomalies in the specific heat and compressibility in pressurized golden SmS and provides a cue to clarify recently-observed anomalies in black SmS.

5 pages, 5 figures

References in corpus (4)

• Quantum Valence Criticality as Origin of Unconventional Critical Phenomena
• Topological properties and the dynamical crossover from mixed-valence to Kondo-lattice behavior in golden phase of SmS
• Excitonic Instability in the Transition from the Black Phase to the Golden Phase of SmS under Pressure Investigated by Infrared Spectroscopy
• Excitonic Bound State in the Extended Anderson Model with c-f Coulomb Interaction

Cited by in corpus (5)

• Surface valence transition in SmS by alkali metal adsorption
• Pressure induced electronic transitions in Samarium monochalcogenides
• Current-Induced Metallization and Valence Transition in Black SmS
• Photo-induced nonlinear band shift and valence transition in SmS
• Photo-induced phase transition on black samarium monosulfide