Department of Chemical Engineering and Materials Science Michigan State University East Lansing, Michigan 48824, USA.
Phys Rev Lett. 2011 Dec 2;107(23):235901. doi: 10.1103/PhysRevLett.107.235901. Epub 2011 Nov 30.
Fully dense crystalline solids with extremely low lattice thermal conductivity (κ(L)) are of practical importance for applications including thermoelectric energy conversion and thermal barrier coatings. Here we show that lone-pair electrons can give rise to minimum κ(L) in chalcogenide compounds that contain a nominally trivalent group VA element. Electrostatic repulsion between the lone-pair electrons and neighboring chalcogen ions creates anharmonicity in the lattice, the strength of which is determined by the morphology of the lone-pair orbital and the coordination number of the group VA atom.
具有极低晶格热导率（κ（L））的全致密晶体固体对于包括热电能量转换和热障涂层在内的应用具有实际意义。在这里，我们表明孤对电子可以在包含名义上三价的 VA 族元素的硫属化合物中导致最低的 κ（L）。孤对电子和相邻的硫属离子之间的静电排斥在晶格中产生非谐性，其强度由孤对轨道的形态和 VA 族原子的配位数决定。
