Nano-scale compositional oscillation and phase intergrowth in Cu_(2)S_(0.5)Se_(0.5) and their role in thermal transport  

作　　者：Yuyu Wei Ping Lu Chenxi Zhu Kunpeng Zhao Xun Shi Lidong Chen Fangfang Xu 

机构地区：[1]State Key Laboratory of High Performance Ceramics and Superfine Microstructures,Shanghai Institute of Ceramics,Chinese Academy of Sciences(CAS),Shanghai 200050,China [2]Center of Materials Science and Optoelectronics Engineering,University of Chinese Academy of Sciences,Beijing 100049,China [3]State Key Laboratory of Metal Matrix Composites,School of Materials Science and Engineering,Shanghai Jiao Tong University,Shanghai 200240,China

出　　处：《Journal of Materials Science & Technology》2021年第20期222-229,共8页材料科学技术（英文版）

基　　金：This work was financially supported by the National Natural Science Foundation of China(Nos.51672296,51625205 and51902199);the Science and Technology Commission of ShanghaiMunicipality(No.16DZ2260603);the Shanghai Technical Platform for Testing and Characterization on Inorganic Materials(No.19DZ2290700)。

摘　　要：Solid solution alloying is a promising strategy to establish high performance thermoelectrics.By alloying different elements,phase structures and phase compositions may vary accompanied by appearance of variety of interesting microstructures including mass fluctuation,lattice strain,nano-scale defects and spinodal decomposition,all of which may greatly influence the electrical and specifically the thermal transport of the material.In the present study,atomic structures of Cu_(2)S_(0.5)Se_(0.5) solid solution have been examined by using atom-resolved electron microscopy in order to investigate the structure-correlated physical insights for the abnormal thermal transport in this solid solution.Then the exceptional intergrowth nanostructures were observed.The solid solution consists of two high symmetrical phases,i.e.the hexagonal and cubic phase,which alternately intergrow to form highly oriented ultra-thin lamellae of nano or even,unit cell scales.The compositional oscillation in Se/S atomic ratio during alloying is responsible for the phase stability and intergrowth nanostructures.The unique binary phase intergrowth nanostructures make great contribution to the ultra-low lattice thermal conductivity comparable to glass and extremely short phonon mean free path of only 1.04Å,peculiar continuous hexagonal-to-cubic structural transformation without a critical transition temperature and its corresponding abnormal changes of thermal characters with temperatures.The present study further evokes the unlimited possibilities and potentials for tailoring nanostructures by alloying for improved thermoelectric performance.

关 键 词：THERMOELECTRIC Solid solution Intergrowth nanostructures Compositional oscillation Structural transformation Thermal transport 

分 类 号：TB383.1[一般工业技术—材料科学与工程]