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3C-SiC高压相变的理论研究
引用本文:吕梦雅,陈洲文,李立新,刘日平,王文魁. 3C-SiC高压相变的理论研究[J]. 物理学报, 2006, 55(7): 3576-3580
作者姓名:吕梦雅  陈洲文  李立新  刘日平  王文魁
作者单位:(1)亚稳材料制备技术与科学国家重点实验室,燕山大学,秦皇岛 066004; (2)亚稳材料制备技术与科学国家重点实验室,燕山大学,秦皇岛 066004;燕山大学信息科学与工程学院,秦皇岛 066004
摘    要:
基于GGA近似使用第一性原理方法对3C-SiC的ZB至NaCl相的高压相变过程进行了研究,得出中间过渡相的最高对称性为Imm2(而此前有研究认为是Cmm2和Pmm2),激活焓计算值为0.647eV,与Catti等人的结果很接近.尽管如此,计算的相变压力为69GPa仍然比实验值100GPa小很多,可能是由于实验中的相转变具有较大的滞后性.对相变压力时两相的能带结构也作了计算和分析,可以得出相变过程除几何结构的重构之外还伴随着半导体—金属的电子转变,这对于实验上准确判断相变点有一定的指导意义.关键词:高压相变第一性原理3C-SiC激活焓

关 键 词:高压相变  第一性原理  3C-SiC  激活焓
文章编号:1000-3290/2006/55(07)/3576-05
收稿时间:2005-09-14
修稿时间:2005-09-142006-01-11

Theoretical study of phase transition of 3C-SiC under high pressure
Lü Meng-Ya,Chen Zhou-Wen,Li Li-Xin,Liu Ri-Ping,Wang Wen-Kui. Theoretical study of phase transition of 3C-SiC under high pressure[J]. Acta Physica Sinica, 2006, 55(7): 3576-3580
Authors:Lü Meng-Ya  Chen Zhou-Wen  Li Li-Xin  Liu Ri-Ping  Wang Wen-Kui
Abstract:
Based on the generalized gradient approximation, we have investigated the phase transition of 3C-SiC from ZB to NaCl structure using first-principles method, and obtained the accurate symmetry Imm2 (previously regarded as lower symmetry Cmm2 and Pmm2) of the intermediate phase. The relative activation enthalpy 0.647eV is close to the result of Catti. The obtained transition pressure 69GPa is lower than the experimental value of 100GPa which may be attributed to the hysteresis of the phase transition. Meanwhile, the energy bands for ZB- and NaCl-SiC were also calculated and discussed, the results suggest that the phase transition of 3C-SiC is accompanied by an electronic transition from semiconducting to metallic character besides the structure reconstruction, which may be useful for the accurate determination of the transition pressure.
Keywords:3C-SiC
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