压力下NaN_3结构稳定性、力学性质和电子结构的理论研究  

Theoretical research on structure stabilities,mechanical properties and electronic structures of NaN_3 under pressure

作　　者：余飞[1] 

机构地区：[1]西南民族大学电气信息工程学院,四川成都610041

出　　处：《西南民族大学学报（自然科学版）》2017年第3期314-320,共7页Journal of Southwest Minzu University(Natural Science Edition)

基　　金：国家民委科研项目(NO.14XNZ018)

摘　　要：采用基于密度泛函理论的从头算平面波超软贋势方法研究了压力对NaN_3结构稳定性、力学性能以及电子结构的影响.对能量和力学参量的计算结果表明,R-3m结构是NaN_3在零压下的稳定性结构.随着压力的增加,在5 GPa的压力范围内NaN_3会发生从R-3m结构到C2/m结构的结构相变,而C2/m结构的NaN_3在压力超过20 GPa以后也不能够保持稳定.该结果与实验研究结果间取得了很好的一致.此外,对电子结构的研究表明,常压下两种结构NaN_3都表现出了绝缘体的性质.随着压力的增加,C2/m结构NaN_3的价带和导带宽度都略有增加,而带隙宽度略有减小.The structural stabilities, mechanical properties and electronic structures of NaN3 under pressure were investigated u- sing the first-principle plane-wave ultrasoft pseudopotential methods based on the density functional theory. The calculated re- suits showed that R-3m structure was the stable structure of NaN3 at atmospheric pressure. As the pressure increased, NaN3 un- derwent a pressure-induced phase transition from R-3m structure to C2/m structure and the transition pressure was less than 5 GPa. Once the pressure exceeded 20 GPa, C2/m structure NaN3 could not keep stable. The results agreed well with previous ex- perimental results. Moreover,electronic structure calculations revealed that R-3m and C2/m structure NaN3was isolator. For C2/ m structure NaN3 , with the increase of pressure, the valence band and conduction band became broader and the band gap values tended to decrease.

关 键 词：NA N3 平面波超软贋势 高压性质 

分 类 号：O521[理学—高压高温物理]