Theoretical investigations of electrical transport properties in CoSb3 skutterudites under hydrostatic loadings

作     者：Chongze Hu Peter Ni Li Zhan Huijuan Zhao Jian He Terry M. Tritt Jingsong Huang Bobby G. Sumpter 

作者机构：Department of Mechanical Engineering Clemson UniversityClemson SC 29634 USA Department of Mechanical Engineering University of Minnesota-Twin Cities Minneapolis MN 55455 USA Montgomery High School Skillman NJ 08558 USA Department of Physics and Astronomy Clemson UniversityClemson SC 29634 USA Center for Nanophase Materials Sciences and ComputationalSciences and Engineering Division Oak Ridge National Laboratory Oak Ridge TN 37831 USA 

出 版 物：《Rare Metals》 (稀有金属（英文版）)

年 卷 期：2018年第37卷第4期

页      面：316-325页

核心收录：

学科分类：08[工学] 080501[工学-材料物理与化学] 0805[工学-材料科学与工程（可授工学、理学学位）] 

基　　金：supported by the Office of Science of the US Department of Energy (Nos. DEAC05-00OR22750 and DE-AC02-05-CH11231) the support of National Science Foundation (No. DMR-1307740) 

主　　题：CoSb3 skutterudite Hydrostatic loadingsMechanical properties Electronic structure Seebeckcoefficient Thermoelectrics 

摘      要：CoSb3-based mark mid-temperature skutterudites have been a benchthermoelectric material under intensive experimental and theoretical studies for decades. Doping and filling, to the first order, alter the crystal lattice constant of CoSb3 in the context of ＂chemical pressure.＂ In this work, we employed ab initio density functional theory in conjunction with semiclassical Boltzmann transport theory to investigate the mechanical properties and especially how hydrostatic loadings, i.e., ＂physical pressure,＂ impact the electronic band structure, Seebeck coefficient, and power factor of pristine CoSb3. It is found that hydrostatic pressure enlarges the band gap, suppresses the density of states （DOS） near the valence band edge, and fosters the band convergence between the valley bands and the conduction band minimum （CBM）. By contrast, hydrostatic tensile reduces the band gap, increases the DOS near the valence band edge, and diminishes the valley bands near the CBM. Therefore, applying hydrostatic pressure provides an alternative avenue for achieving band convergence to improve thermoelectric properties of N-type CoSb3, which is further supported by our carrier concentration studies. These results provide valuable insight into the further improvement of thermoelectric performance of CoSb3-based skutterudites via a synergy of physical and chemical pressures.