Glassy atomic vibrations and blurry electronic structures created by local structural disorders in high-entropy metal telluride superconductors
Glassy atomic vibrations and blurry electronic structures created by local structural disorders in high-entropy metal telluride superconductors
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DOI：
10.1016/j.mtphys.2023.101019
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发表时间：
2022-09
影响因子：
11.5
通讯作者：
Y. Mizuguchi;H. Usui;R. Kurita;Kyohei Takae;M. R. Kasem;R. Matsumoto;Kazuki Yamane;Y. Takano;Y. Nakahira;A. Yamashita;Y. Goto;A. Miura;C. Moriyoshi
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文献类型：
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作者：
Y. Mizuguchi;H. Usui;R. Kurita;Kyohei Takae;M. R. Kasem;R. Matsumoto;Kazuki Yamane;Y. Takano;Y. Nakahira;A. Yamashita;Y. Goto;A. Miura;C. Moriyoshi
最近，在高熵（HE）金属碲化物（MTe）中观察到了超导电性对外压的鲁棒性。在此，我们研究了在M位上具有不同混合组态熵（ΔSmix）的MTe的原子位移参数（Uiso）、原子振动特性和电子结构，以了解超导性稳定性的起源.当ΔSmix≥ 1.1R时，M位合金化明显增加了MTe的原子位移参数（Uiso）、原子振动特性和电子结构，这是NaCl型（低压）相产生局部无序的证据.模拟的振动态密度（DOS）在ΔSmix≥ 1.1R时有明显的展宽，表明NaCl型相的原子振动具有玻璃态特征。在CsCl型（高压）相的计算电子结构中，随着ΔSmix的增加，出现模糊的电子能带结构，这表明具有CsCl型结构的HE MTe中的模糊电子态的演化。在费米能下的电子态密度不能解释传统的电子-声子超导时HE-MTe的Tc的变化，但传统的解释似乎对PbTe起作用。因此，在HE MTe的配对机制的玻璃声子和/或模糊的电子状态的影响，和超导的鲁棒性可能源于独特的电子-声子耦合。
Recently, robustness of superconductivity to external pressure has been observed in high-entropy (HE) metal telluride (MTe). Here, we investigated the atomic displacement parameters (Uiso), atomic vibration characteristics, and electronic structure of MTe with various configurational entropies of mixing (ΔSmix) at the M site to understand the origin of the robustness of the superconductivity.Uisoclearly increased by M-site alloying with ΔSmix≥ 1.1R, 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 ΔSmix≥ 1.1R, 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 ΔSmix, 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 inTcfor 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.