论文标题
部分可观测时空混沌系统的无模型预测
Glassy atomic vibrations and blurry electronic structures created by local structural disorders in high-entropy metal telluride superconductors
论文作者
论文摘要
这项工作的动机是我们最近观察到高渗透（HE）超导体AG0.2IN0.2SN0.2SN0.2PB0.2BI0.2BI0.2TE（CSCL-TYPE）对外部压力的鲁棒性。 AG0.2IN0.2SN0.2PB0.2BI0.2TE的超导过渡温度（TC）几乎与压力相关，被称为超导对压力的鲁棒性，而混合混合的零构型熵的PBTE则在TC中呈明显降低。在这里，我们研究了原子位移参数（UISO），原子振动特性和Metal tellurides（MTE）的电子状态，并在M位点具有各种混合（DSMIX）的配置熵。通过与DSMIX> 1.1R的M点合金，METET的UISO显然增加了，这是DSMIX通过三个或更多M元素的溶液增加而引起的局部疾病的证据。揭示的状态振动密度（DOS）显示了DSMIX> 1.1R的显着拓宽，这表明具有NaCl型结构（低压阶段）的He MTE中原子振动的玻璃特征。在观察到TC的鲁棒性的CSCL型（高压）阶段的电子状态下，模糊的电子带结构随着DSMIX的增加而出现，这表明具有CSCL型结构的MTE中模糊（玻璃）电子状态的演变。当假设传统的电子 - 音波超导性时，费米能量的估计电子DOS无法解释HE MTE的变化，但是常规解释似乎对PBTE起作用。因此，MTE中与DSMIX> 1.1R的配对机制受MTE中玻璃状声子和/或模糊的电子状态的影响，超导性的鲁棒性将来自独特的电子 - phonon耦合。
The motivation of this work is our recent observation of the robustness of superconductivity in a High-entropy (HE) superconductor Ag0.2In0.2Sn0.2Pb0.2Bi0.2Te (CsCl-type) to external pressure. The superconducting transition temperature (Tc) of Ag0.2In0.2Sn0.2Pb0.2Bi0.2Te is almost constant with pressure, described as robustness of superconductivity to pressure, whereas the PbTe with zero configurational entropy of mixing exhibits a clear decrease in Tc with pressure. Here, we investigated the atomic displacement parameters (Uiso), the atomic-vibration characteristics, and the electronic states of metal tellurides (MTe) with various configurational entropy of mixing (DSmix) at the M site. The Uiso for the M site is clearly increased by M-site alloying with DSmix > 1.1R, which is the evidence of local disorder introduced by the increase in DSmix via the solution of three or more M elements. The revealed vibrational density of states (DOS) shows a remarkable broadening with DSmix > 1.1R, which indicates glassy characteristics of atomic vibration in HE MTe with a NaCl-type structure (low-pressure phase). On the electronic states of the CsCl-type (high-pressure) phases, where the robustness of Tc is observed, blurry electronic band structure appears with increasing DSmix, which indicates the evolution of blurry (glassy) electronic states in HE MTe with the CsCl-type structure. The estimated electronic DOS at Fermi energy cannot explain the changes in Tc for HE MTe when assuming conventional electron-phonon superconductivity, but the conventional explanation seems to work for PbTe. Therefore, the pairing mechanisms in MTe with DSmix > 1.1R are affected by glassy phonon and/or blurry electronic states in MTe, and the robustness of superconductivity would be originating from unique electron-phonon coupling.
