Topological properties and the dynamical crossover from mixed-valence to Kondo-lattice behavior in golden phase of SmS

TL;DR

This study explores the temperature-dependent electronic and topological changes in the golden phase of SmS, revealing a Lifshitz transition and non-topological surface states, and identifies universal energy scales in Kondo/mixed-valent systems.

Contribution

It provides a detailed analysis of the topological and electronic crossover in SmS using dynamical mean-field theory, highlighting the non-topological nature of surface states and universal energy scales.

Findings

Formation of hybridization-induced pseudogap upon cooling

Fermi surface topology undergoes a Lifshitz-like transition

Surface states are Rashba spin-polarized, not topologically protected

Abstract

We have investigated temperature-dependent behaviors of electronic structure and resistivity in a mixed-valent golden phase of SmS, based on the dynamical mean-field theory band structure calculations. Upon cooling, the coherent Sm 4$f$ bands are formed to produce the hybridization induced pseudogap near the Fermi level, and accordingly the topology of Fermi surface is changed to exhibit a Lifshitz-like transition. The surface states emerging in the bulk gap region are found to be not topologically protected states but just typical Rashba spin-polarized states, indicating that SmS is not a topological Kondo semimetal. From the analysis of anomalous resistivity behavior in SmS, we have identified universal energy scales, which characterize the Kondo/mixed-valent semimetallic systems.