Transport and thermodynamic properties under anharmonic motion in type-I Ba8Ga16Sn30 clathrate

作     者：Xiang Zheng Sergio Y. Rodriguez Laziz Saribaev Joseph H. Ross, Jr. 

作者机构：Department of Physics and Astronomy Texas A&M University College Station Texas 77843 USA Materials Science and Engineering Program Texas A&M University College Station Texas 77843 USA 

出 版 物：《Physical Review B》 (Phys. Rev. B Condens. Matter Mater. Phys.)

年 卷 期：2012年第85卷第21期

页      面：214304-214304页

核心收录：

学科分类：07[理学] 0702[理学-物理学] 

基　　金：National Science Foundation, NSF Directorate for Mathematical and Physical Sciences, MPS, (0103455) 

主　　题：TRANSPORT theory (Mathematics) THERMODYNAMICS HARMONIC oscillators MOLECULAR dynamics CLATHRATE compounds BARIUM compounds THERMOELECTRICITY 

摘      要：Anharmonic guest atom oscillation has direct connection to the thermal transport and thermoelectric behavior of type-I Ba8Ga16Sn30 clathrates. This behavior can be observed through several physical properties, with for example the heat capacity providing a measure of the overall excitation level structure. Localized anharmonic excitations also influence the low-temperature resistivity, as we show in this paper. By combining heat capacity, transport measurements, and our previous NMR relaxation results, we address the distribution of local oscillators in this material, as well as the shape of the confining potential and the excitation energies for Ba(2) ions in the cages. We also compare to the soft-potential model and other models used for similar systems. The results show good agreement between the previously deduced anharmonic rattler potential and experimental data.