南京大学学报（自然科学版）2018，Vol.54Issue(3)：580-589,10.DOI:10.13232/j.cnki.jnju.2018.03.013
CaX(X=S,Se,Te)晶格热导率的第一性原理计算
First principle calculations of the lattice thermal conductivity and phonon scattering process of CaX(X=S,Se,Te)
郑安坤 1杜永平2
作者信息
- 1. 南京大学固体微结构实验室,南京,210093
- 2. 南京理工大学物理学院,南京,210094
- 折叠
摘要
Abstract
In this paper,the properties of phonon and thermal conductivity of CaX(X=S,Se,Te)is systematically studied by using the pseduedo-potential plane wave method in the framework of density functional theory(DFT) cooperated with superell method which is used to calculated force constant in crystls.Various phonon properties including phonon specturm,total and atom projected phonon density of states are calulated with second order force constants.Similarities and differences of the phonon spectrum and density of states of these three semiconductors are analyzed and explained by physical properties of compostions in these compounds.Future,thermal conductivies of these semiconductors are calculated using third order force constants which are calculated in the framework of anharmonic approximation and three phonon scattering theory.Calculated thermal conductivities are analyzed and compared when X in CaX changes from Te to S.In order to explain the different behaviors in their thermal conduc-tivities,mode dependent thermal conductivities are calculated and used to analyze which phonon mode in these semiconductors contributes most to their thermal conductivity,mode dependent Grüneisen parameter are calculated and used to analyze which phonon mode may have larger anharmonicity,scattring phase space are calculated and used to analyze which mode have more three phonon scattring channel.At the end,the direct influence factors of thermal conductivity,mode dependent phonon group velocity and mode dependent phonon lifetime under 300 K are calculated and analyzed to expain the differences the their thermal conductivity.关键词
第一性原理/声子/晶格热导率/散射Key words
first principle/phonon/lattice thermal conductivity/scattering分类
数理科学引用本文复制引用
郑安坤,杜永平..CaX(X=S,Se,Te)晶格热导率的第一性原理计算[J].南京大学学报（自然科学版）,2018,54(3):580-589,10.
