Glassy atomic vibrations and blurry electronic structures created by local structural disorders in high-entropy metal telluride superconductors. (March 2023)

• Record Type: Journal Article
• Authors: Mizuguchi, Yoshikazu; Usui, Hidetomo; Kurita, Rei; Takae, Kyohei; Kasem, Md Riad; Matsumoto, Ryo; Yamane, Kazuki; Takano, Yoshihiko; Nakahira, Yuki; Yamashita, Aichi; Goto, Yosuke; Miura, Akira; Moriyoshi, Chikako
• Is Part Of: Materials today physics. Volume 32(2023)
• Publication Date: 2023-03
• Subjects: High entropy materials -- Superconductivity -- Local disorder -- MD simulation -- Band calculations; Materials science -- Periodicals; Physics -- Periodicals; Electronic journals; 530.41
• DOI: 10.1016/j.mtphys.2023.101019
• Languages: English
• ISSNs: 2542-5293

Abstract

Abstract: Recently, robustness of superconductivity to external pressure has been observed in high-entropy (HE) metal telluride (MTe). Here, we investigated the atomic displacement parameters ( U iso ), atomic vibration characteristics, and electronic structure of MTe with various configurational entropies of mixing (Δ S mix ) at the M site to understand the origin of the robustness of the superconductivity. U iso clearly increased by M-site alloying with Δ S mix ≥ 1.1 R, which is evidence of the created local disorder in the NaCl-type (low-pressure) phases. The simulated vibrational density of states (DOS) shows remarkable broadening with Δ S mix ≥ 1.1 R, which indicates the glassy characteristics of atomic vibrations in the NaCl-type phases. In the calculated electronic structure for the CsCl-type (high-pressure) phases, a blurry electronic band structure appears with increasing Δ S mix, which indicates the evolution of blurry electronic states in HE MTe with the CsCl-type structure. The estimated electronic DOS at the Fermi energy cannot explain the changes in T c for HE MTe when assuming conventional electron-phonon superconductivity, but the conventional explanation seems to work for PbTe. Therefore, the pairing mechanisms in HE MTe are affected by the glassy phonon and/or blurry electronic states, and the robustness of superconductivity possibly originates from the unique electron-phonon coupling. Graphical abstract: Image 1 Highlights: High-entropy metal telluride superconductors exhibits robustness of superconductivity under pressure. With increasing configurational entropy, glassy atomic vibration is induced. Blurred electronic structure is induced by an increase in configurational entropy.