Uniform electronic states and $s$-wave superconductivity in a strongly disordered high-entropy compound (RuRhPdIr)$_{0.6}$Pt$_{0.4}$Sb

Yufu Yamada; Shunsaku Kitagawa; Taishi Ihara; Kenji Ishida; Naoto Uematsu; Daigorou Hirai; Koshi Takenaka

doi:10.1103/b4nw-c4zy

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arXiv · 2508.00342

Uniform electronic states and $s$-wave superconductivity in a strongly disordered high-entropy compound (RuRhPdIr)$_{0.6}$Pt$_{0.4}$Sb

Yufu Yamada·Shunsaku Kitagawa·Taishi Ihara·Kenji Ishida·Naoto Uematsu·Daigorou Hirai·Koshi Takenaka

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Abstract

High-entropy compounds, where multiple elements occupy a single crystallographic site in a highly disordered manner, challenge conventional understandings of electronic structure based on periodicity and well-defined band dispersion. Here, we report a detailed nuclear magnetic resonance study of the high-entropy superconductor (RuRhPdIr)$_{0.6}$Pt$_{0.4}$Sb, revealing a spatially homogeneous electronic environment in the normal state, in stark contrast to its crystallographically disordered lattice. The superconducting state exhibits a small but solid Hebel-Slichter coherence peak followed by a significant decrease in the nuclear spin-lattice relaxation rate, providing compelling evidence for fully gapped $s$-wave pairing. Our findings not only deepen the understanding of superconductivity in highly disordered quantum materials but also open a new pathway for exploring novel superconducting states in entropy-stabilized systems.

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Yufu Yamada, Shunsaku Kitagawa, Taishi Ihara, Kenji Ishida, Naoto Uematsu, Daigorou Hirai, Koshi Takenaka. 2025-08-01. Uniform electronic states and $s$-wave superconductivity in a strongly disordered high-entropy compound (RuRhPdIr)$_{0.6}$Pt$_{0.4}$Sb. https://doi.org/10.1103/b4nw-c4zy

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