Study of the domain-dependent local structure and disorder of high entropy REOBiS2 superconductors

The REOBiS2 (RE = rare earth) family of layered chalcogenides exhibits remarkable functional properties, including superconductivity and thermoelectricity. Recent studies show that superconductivity can be tuned by increasing configurational entropy at the RE site via high-entropy alloying (HEA). Preliminary measurements reveal electronic phase separation, with metallic domains embedded in an insulating matrix, likely governed by local structural disorder and mixed-valence RE (3+/4+) states. This project aims to investigate the domain-dependent local structure of HEA REOBiS2 compounds via micro-XAS, correlating entropy with electronic properties. By mapping the spatial distribution of RE elements and linking it to local disorder, we seek to establish a quantitative relationship between entropy, atomic structure, and superconductivity, providing key insights for tuning material functionalities.