HSE方法研究Cd_(1-x)Zn_xTe合金的性质  

Cd_(1-x)Zn_xTe alloys properties studied with the Heyd-Scuseria-Ernzerhof screened hybrid density functional

作　　者：徐海涛[1] 徐闰[1] 王林军[1] 朱燕艳[2] 

机构地区：[1]上海大学材料科学与工程学院,上海200072 [2]上海电力学院数理学院,上海200090

出　　处：《红外与毫米波学报》2012年第5期411-415,461,共6页Journal of Infrared and Millimeter Waves

基　　金：上海市重点学科(S30107);上海市科委重点项目资助(11530500200);上海市教育委员会科研创新项目资助(12ZZ096)~~

摘　　要：采用HSE杂化势计算了Cd1-xZnxTe合金的性质,并获得了较传统GGA更为准确的光学带隙和形成焓.在构建超胞计算合金体系时,采用SQS模型.计算分析得出Cd1-xZnxTe合金的光学带隙下凹参数为0.266 eV,这与已报道实验结果 0.254 eV非常吻合.同时,计算得出的形成焓较高,特别是在Cd0.5Zn0.5Te合金组分时(25.60 meV/at-om).对合金中键长的分析后得出Cd-Te键和Zn-Te键的局域键长与CdTe和ZnTe体材料的值非常接近,但二者之间相差较大,从而导致合金材料中各个原子存在较大的弛豫,这也是该合金具有较大形成焓的主要原因.Heyd-Scuseria-Ernzerh of screened hybrid density functional was used to calculate the band gap and the formation enthalpy of Cd1-xZnxTe alloys, which are much more accurate than the traditional GGA methods. Special quasirandom structure was used to describe the disordered Cd1-xZnxTe alloys. The band gap bowing parameter of Cd1-xZnxTe alloys is 0. 266eV, which is consistent with the experimental value of about 0.254eV. The calculated results show that the formation enthalpy of Cd1-xZnxTe alloys is relatively high, especially for Cd0.5 Zn0.5 Te alloy （25.60meV/atom）. The difference between local bond lengths of Cd-Te and Zn-Te that are very close to those in bulk CdTe and ZnTe is quite large, indicating that the large relaxation exists in these alloys and this relaxation may lead to the large formation enthalpy described above.

关 键 词：Cd1-xZnxTe合金 HSE杂化势 形成焓 光学带隙 第一性原理 

分 类 号：TN304.2[电子电信—物理电子学]