Co掺杂β-FeSi2化合物的热电性能及电子结构的第一性原理研究  

Thermoelectric Properties and First Principle Study on Electronic Structure of Co Doped β-FeSi_2 Compounds

作　　者：李翔[1,2] 周园[1] 任秀峰[1] 年洪恩[1] 曹萌萌[1,2] 

机构地区：[1]中国科学院青海盐湖研究所,中国科学院盐湖资源与化学重点实验室,西宁810008 [2]中国科学院研究生院,北京100049

出　　处：《人工晶体学报》2012年第3期727-732,共6页Journal of Synthetic Crystals

基　　金：中国科学院知识创新工程(KZCXZ-YW-343999000804)

摘　　要：采用机械合金化结合后续热处理成功制备出Fe1-xCoxSi2化合物,探讨Co掺杂对化合物热电性能的影响;利用基于密度泛函理论赝势平面波方法对Co掺杂前后β-FeSi2的电子结构进行计算。结果表明:Co元素掺杂量x应控制在0～0.05之间;β-FeSi2的费米面位于价带顶,其电阻率随温度升高而降低,为非简并半导体;Co掺杂后费米面进入导带底,使其成为n型简并半导体,电阻率较掺杂前大幅度降低;本实验条件下,热电性能检测发现,当x=0.03,温度873 K时,试样的功率因子达到最大值为60μW.m-1.K-2。Fe1-xCoxSi2 compounds were prepared by mechanical alloying combined with sintering process.The effect of Co doping on the thermoelectric properties was studied.The electronic structure of Fe-doped and undoped compounds was calculated using the first principle plane-wave pseudo-potential based on the density function theory.The experimental and calculated results show that the value of concentration x of Co was between 0 and 0.05.Fermi surface of β-FeSi2 locates valence band edge,indicating that β-FeSi2 is a semiconductor and its electrical resistivity decreases as the temperature increasing.The Fermi surface of Co-doped compound moves to the bottom of conduction band and its electrical resistivity increases as the temperature increasing,exhibiting n-type degenerated semiconductor character.Under the condition of experiment,thermoelectrical properties of the sample found the maximum power factor of sample reached 60 μW·m-1·K-2 at 873 K when x=0.03.

关 键 词：Fe1-xCoxSi2 机械合金化 热电性能 能带结构 态密度 

分 类 号：TN304.2[电子电信—物理电子学]