高压下新型双“A”层MAX相V_(2)Ga_(2)C的密度泛函理论研究  

Density Functional Theory of New Double“A”Layer MAX Phase V_(2)Ga_(2)C under High Pressure

作　　者：王腾飞 李小雷[1] 李露 李东 王军凯 WANG Tengfei;LI Xiaolei;LI Lu;LI Dong;WANG Junkai(School of Materials Science and Engineering,Henan Polytechnic University,Jiaozuo 454003,Henan,China)

机构地区：[1]河南理工大学材料科学与工程学院,河南焦作454003

出　　处：《高压物理学报》2021年第3期49-54,共6页Chinese Journal of High Pressure Physics

基　　金：国家自然科学基金(51001042);河南省科技攻关计划(212102210589);省部共建耐火材料与冶金国家重点实验室开放基金(G201904);河南理工大学博士基金(B2019-40)。

摘　　要：基于密度泛函理论的第一性原理,研究了压强对双“A”层MAX相V_(2)Ga_(2)C晶体结构、弹性和电子性质的影响,并利用玻恩稳定准则预测了V_(2)Ga_(2)C力学稳定状态下的压强范围。计算结果表明:在0~70 GPa下,V_(2)Ga_(2)C的晶体结构处于力学稳定状态;随着压强的增大,V_(2)Ga_(2)C的晶格常数和体积均有不同程度的缩小,a轴随压强的增大收缩得最快,晶胞体积收缩了24%左右;随着压强的增加,V_(2)Ga_(2)C材料的维氏硬度从0 GPa压强下的18.23 GPa减小为70 GPa压强下的2.30 GPa,在20.15 GPa时从脆性材料转变为韧性材料;V_(2)Ga_(2)C的态密度和能带结构等电子性质随压强的变化较小,即压强对V_(2)Ga_(2)C的电子性质影响不大。The structural,elastic and electronic properties of double“A”layer MAX phase V_(2)Ga_(2)C under high pressure were studied by the first-principles calculations of density functional theory,and the stable state of V_(2)Ga_(2)C was predicted by using the Born stability criteria.The results show that V_(2)Ga_(2)C crystal structure at the state of mechanical stability within the pressure range of 0–70 GPa.With the increase of pressure,the lattice parameters and volumes of V_(2)Ga_(2)C decreased.V2Ga2C is more compressible in the aaxis direction than c-axis direction,and the volume shrinks by about 24%.With increasing pressure,Vickers hardness of V_(2)Ga_(2)C material decreased from 18.23 GPa(0 GPa)to 2.30 GPa(70 GPa),and from brittle material transform into ductile material at 20.15 GPa.With the change of pressure,the electronic properties have changed slightly such as density of states and band structures,which have almost no effect on the electronic properties of V_(2)Ga_(2)C.

关 键 词：MAX相 V_(2)Ga_(2)C 高压 力学稳定性 弹性性质 电子性质 

分 类 号：O521.2[理学—高压高温物理] O413.1[理学—物理]