非谐性
凝聚态物理
声子
不稳定性
价(化学)
晶体结构
格子(音乐)
费米能级
对分布函数
Crystal(编程语言)
态密度
材料科学
物理
化学
结晶学
电子
量子力学
声学
计算机科学
程序设计语言
作者
Riddhimoy Pathak,Sayan Paul,Subarna Das,Anustoop Das,Swapan K. Pati,Kanishka Biswas
标识
DOI:10.1002/anie.202408908
摘要
Pauling’s third empirical rule deals with the cationic repulsion due to proximity in the face or edge shared polyhedra in a crystal structure, can bring about the lattice instability required to suppress the lattice thermal conductivity (κL). Here, we demonstrate the presence of such instability in TlAgSe, leading to a ultra‐low κL of 0.17 W/m.K at 573 K. Our study reveals the instability arising from Ag‐Ag repulsion within edge‐shared AgSe4 tetrahedra through investigation of the local structure using synchrotron X‐ray pair distribution function (PDF) and supported by density functional theory. We observe correlation between weakening in the Ag and the Tl‐sublattice, providing direct experimental evidence of Pauling’s third rule. The correlated rattling of Ag and Tl induces a highly anharmonic lattice and low energy optical phonons, resulting in suppressed sound velocity and ultralow κL. The electronic origin of soft and anharmonic lattice is the presence of filled antibonding states in the valence band near the Fermi level constructed by Ag(4d)‐Se(4p) and Tl(6s)‐Se(4p) interactions. This work demonstrates that the evidence of dynamic distortion in a crystal lattice is governed by the third empirical rule given by Pauling, which can act as a potential new strategy for diminishing κL in crystalline solids.
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