Ground-State Structure and Physical Properties of NB_2 Predicted from First Principles

作     者：吴旌贺 刘长欣 

作者机构：Department of PhysicsHenan Institute of Education 

出 版 物：《Chinese Physics Letters》 (中国物理快报（英文版）)

年 卷 期：2016年第33卷第3期

页      面：78-81页

核心收录：

学科分类：07[理学] 070304[理学-物理化学(含∶化学物理)] 0805[工学-材料科学与工程（可授工学、理学学位）] 0703[理学-化学] 0704[理学-天文学] 

基　　金：Supported by the Natural Science Foundation of Henan Educational Committee under Grant No 2011A140006 the Key Scientific and Technological Project of He'nan Province under Grant No 152102210307 

主　　题：NB is in of Ground-State Structure and Physical Properties of NB2 Predicted from First Principles from 

摘      要：Using the newly developed particle swarm optimization algorithm on crystal structural prediction, we predict a new class of boron nitride with stoicMometry of NB2 at ambient pressure, which belongs to the tetragonal 14m2 space group. Then, its structure, elastic properties, electronic structure, and chemical bonding are investigated by first-principles calculations with the density functional theory. The phonon calculation and elastic constants confirm that the predicted NB2 is dynamically and mechanically stable, respectively. The large bulk modulus, large shear modulus, large Young＇s modulus, and small Poisson＇s ratio show that the 14m2 NB2 should be a new superhard material with a calculated theoretical Vickers hardness value of 66 GPa. Further analysis on density of states and electron localization function demonstrate that the strong B B and 13 N covalent bonds are the main reason for its high hardness in 14m2 NB2.