First-principles study of mechanical stability and thermal properties of MNNi_3 (M=Zn,Mg,Al) under pressure  

作　　者：翟红村 李晓凤 杜军毅 姬广富 

机构地区：[1]Mathematics College,Luoyang Normal College [2]College of Physics and Electronic Information,Luoyang Normal College [3]Laboratory for Shock Wave and Detonation Physics Research Institute of Fluid Physics,Chinese Academy of Engineering Physics

出　　处：《Chinese Physics B》2012年第5期494-500,共7页中国物理B（英文版）

基　　金：Project supported by the National Natural Science Foundation of China(Grant Nos.11147101 and 11071107);the Henan Research Program of Basic and Frontier Technology,China(Grant Nos.112300410024 and 102102210452);the Henan Natural Science Basic Research,China(Grant Nos.2011B140013 and 2010A140011);the Scientific Research Foundation of Luoyang Normal University, China(Grant No.2010-QNJJ-003)

摘　　要：The mechanical stability,elastic,and thermodynamic properties of the anti-perovskite superconductors MNNi 3（M=Zn,Mg,Al） are investigated by means of the first-principles calculations.The calculated structural parameters and elastic properties of MNNi 3 are in good agreement with the experimental and the other theoretical results.From the elastic constants under high pressure,we predict that ZnNNi 3,MgNNi 3,and AlNNi 3 are not stable at the pressures above 61.2 GPa,113.3 GPa,and 122.4 GPa,respectively.By employing the Debye model,the thermodynamic properties,such as the heat capacity and the thermal expansion coefficient,under pressures and at finite temperatures are also obtained successfully.The mechanical stability,elastic,and thermodynamic properties of the anti-perovskite superconductors MNNi 3（M=Zn,Mg,Al） are investigated by means of the first-principles calculations.The calculated structural parameters and elastic properties of MNNi 3 are in good agreement with the experimental and the other theoretical results.From the elastic constants under high pressure,we predict that ZnNNi 3,MgNNi 3,and AlNNi 3 are not stable at the pressures above 61.2 GPa,113.3 GPa,and 122.4 GPa,respectively.By employing the Debye model,the thermodynamic properties,such as the heat capacity and the thermal expansion coefficient,under pressures and at finite temperatures are also obtained successfully.

关 键 词：density functional theory ELASTICITY thermodynamic properties 

分 类 号：O511.4[理学—低温物理]