标题：Electronic and Lattice Vibrational Properties of BaSi_(2) from Density Functional Theory Calculations
作者：H. PENG;C.L. WANG;J.C. LI;R.Z. ZHANG;H.C. WANG;Y. SUN;M. SHENG
作者机构：[Peng, H] School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China;[ Wang, C.L] School of Physics, State 更多
会议名称：29th International Conference on Thermoelectrics (ICT)
会议日期：MAY 30-JUN 03, 2010
来源：Journal of Electronic Materials
关键词：Density function theory;thermodynamic properties;Boltzmann transport
摘要：BaSi_(2) is a potential thermoelectric material because of its very low thermal conductivity. Using the full-potential linearized augmented plane-wave method and semiclassical Boltzmann theory, thermoelectric transport properties of BaSi_(2) have been investigated. The calculations show that the thermoelectric properties can be remarkably improved by optimizing the carrier concentration. The linear response method within the framework of density functional theory was employed to investigate the underlying physics of heat transport. There are rather flat optical dispersion curves and low frequency of acoustic phonon modes in the phonon band structure of BaSi_(2). The low-lying optical phonon branch at the GAMMA point of the Brillouin zone (BZ) corresponds to rigid-unit vibration of the Si tetrahedron. The rigid-unit vibration mode confines the acoustic phonon modes and scatters the heat-carrying acoustic modes, leading to the low lattice thermal conductivity.