红外与毫米波学报, 2012, 31 (5): 411, 网络出版: 2012-10-18
HSE方法研究Cd1-xZnxTe合金的性质
Cd1-xZnxTe alloys properties studied with the Heyd-Scuseria-Ernzerhof screened hybrid density functional
Cd1-xZnxTe合金 HSE杂化势 形成焓 光学带隙 第一性原理 Cd1-xZnxTe alloys HSE screened hybrid density functional formation enthalpy band gap first principle
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/atom).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.
Abstract
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 Cd0.5Zn0.5Te 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.
徐海涛, 徐闰, 王林军, 朱燕艳. HSE方法研究Cd1-xZnxTe合金的性质[J]. 红外与毫米波学报, 2012, 31(5): 411. XU Hai-Tao, XU Run, WANG Lin-Jun, ZHU Yan-Yan. Cd1-xZnxTe alloys properties studied with the Heyd-Scuseria-Ernzerhof screened hybrid density functional[J]. Journal of Infrared and Millimeter Waves, 2012, 31(5): 411.