高压下Si的结构转变与弹性性质的第一性原理计算  

First-principles Investigations on Structural Stability and Elastic Properties of Si under High Pressure

作　　者：辛伟[1,2] 刘鑫[2] 王晓明[2] 张立新[2] 朱秀云[2] 张启周[2] 郝爱民[1,2] 

机构地区：[1]燕山大学亚稳材料制备技术与科学国家重点实验室,河北秦皇岛066004 [2]河北科技师范学院数学与信息科技学院

出　　处：《河北科技师范学院学报》2009年第4期36-40,共5页Journal of Hebei Normal University of Science & Technology

基　　金：中国博士后科学基金(课题编号:20090450924);河北科技师范学院博士启动基金(课题编号:2008YB001);国家自然科学基金(课题编号:50771090)

摘　　要：利用基于密度泛函的第一性原理,计算了在压力作用下Si的结构相变和弹性性质。晶胞总能的计算结果表明,Si在11.7 GPa压力下发生了从立方金刚石结构(Si-Ⅰ)到四方结构(Si-Ⅱ)的转变。能带结构和态密度的计算结果显示,Si-Ⅰ是具有间接带隙的半导体,带隙为0.71 eV,Si-Ⅱ呈现金属的能带结构特性;Si-Ⅰ和Si-Ⅱ费米面附近的能带结构主要来自于2p电子的贡献。高压下Si-Ⅰ的弹性系数计算结果表明,弹性系数C11,C12和C44均随压力的增加呈现线性增大的规律。An investigation on structural stability and elastic properties of Si under high pressure is conducted using first-principles calculations based on density functional theory （DFT）. Our results show that a structural transformation from Si- I to Si- II occurs at 11.7 GPa and that Si- I has indirect band structures with band gap of 0. 71 eV; and Si- II is metallic with several overlaps between conduction bands and valence bands. In addition, the results indicate that the elastic constants C11, C12 and C44 of Si-I increase linearly with pressure.

关 键 词：第一性原理计算 结构转变 弹性系数 高压 

分 类 号：O482.1[理学—固体物理]