Cr_2AlC中空位相关属性及电子结构的第一性原理研究  

First principles study of the vacancy effect on the structure and electronics properties of Cr_2AlC

作　　者：彭飞[1] 

机构地区：[1]上海电子信息职业技术学院电子工程系,上海201411

出　　处：《西北师范大学学报（自然科学版）》2016年第4期27-31,共5页Journal of Northwest Normal University(Natural Science)

基　　金：国家自然科学基金资助项目(11304324)

摘　　要：通过第一性原理研究了Cr_2AlC中空位对其结构和电子性质的影响.在Cr_2AlC中,Cr,Al和C空位形成能分别为1.15eV(Cr-poor)、-1.93eV(Cr-rich),2.02eV(Al-poor)、-4.38eV(Al-rich)和1.14eV(C-rich)、-3.05eV(C-poor).计算结果表明,Al空位的形成能相对较大,这意味着在Cr_2AlC中,Al空位最不容易形成;在一定温度下,Cr_2AlC中Al空位的浓度较低;通过态密度的研究发现,在Cr_2AlC中,Cr-C共价键和Cr-Al金属键共存;当形成Al空位时,Cr_2AlC的导电性明显降低.The vacancy related properties and electronics structure of Cr2AlC are investigated by first principles method.The Cr,Al and C vacancy formation energies are 1.15eV（Cr-poor）,-1.93eV（Crrich）,2.02eV（Al-poor）,-4.38eV（Al-rich）and 1.14eV（C-poor）,-3.05eV（C-rich）,respectively.The results show that the Al vacancy formation energy is higher than the other two types of vacancy formation energy,which means that the Al vacancy is not the energetically most favorable in Cr2AlC.It is also noted that the Al vacancy concentration is the lowest at a specific temperatures.The DOS of Cr2AlC shows that the Cr-C covalent bond and the Cr-Al metallic bond mainly co-exist in Cr2AlC.The conductivity is clearly decreased when the Al vacancy formed,owing to the formation of the Al2O3 protective layer.

关 键 词：Cr2AlC 第一性原理 空位 形成能 共价键 

分 类 号：TL99[核科学技术—核技术及应用]