高压下硅烷的第一性原理研究  

On First Principles of Silane at High Pressure

作　　者：肖芬[1] 娄姗姗[1] 胡发波 杨皎[1] 刘福生[2] 田春玲[1] 

机构地区：[1]西南大学物理科学与技术学院,重庆400715 [2]西南交通大学高温高压物理研究所,成都610031

出　　处：《西南大学学报（自然科学版）》2016年第9期153-158,共6页Journal of Southwest University(Natural Science Edition)

基　　金：国家重点基础研究发展计划(973计划)(2011CB808201)

摘　　要：利用一种新发展的从头算演化方法,对高压下固态硅烷进行分子晶体结构预测,重点关注硅烷在25-300GPa压力区间相结构的变化,以及金属相结构的转变条件.当加压至55GPa时,除了搜索到与最新金刚石压砧实验结果一致的结构（I-42d,I41/a）以外,同时还搜索到新的C2/c结构,并与I41/a结构共同稳定存在于55-240GPa的压力区间.在上述整个压力范围,硅烷均保持良好的绝缘性,直至压力达到240GPa才转变为Pbcn结构,并表现出金属性.结果较好地解释了已有的实验高压状态方程数据;验证了硅烷的金属化相变仅发生在200GPa以上,排除硅烷在60GPa发生金属化相变而导致其失去透明性的可能性.High-pressure phases of silane are predicted by using the ab initio evolution theory in pressure region from 25 to 300GPa.The molecular crystal structure prediction method has been used to search the stable structures of silane.At 55 GPa,three stable phases have been found,two of them are in I-42 dand I41/a structures and in a good agreement with the experimental results of diamond anvil cell（DAC）.A new phase has been predicted,which has C2/c structure.Increasing with pressure,the I-42 dphase becomes unstable,only C2/c phase is coexistence with I41/a between 55 and 240GPa,and both of them keep in insulated state.At pressure increased to 240 GPa,crystal silane transforms to Pbcn structure and becomes a metal.This work well explains the experimental equation of state at high pressure,and eliminates the possibility that loss of transparency for silane at 60 GPa is due to the metallization.

关 键 词：硅烷 高压结构 第一性原理 

分 类 号：O469[理学—凝聚态物理]