First-Principles study of Elastic properties, Hardness and Debye temperature of O-BN under pressures

2017 3rd International Conference on Energy, Environment and Materials Science

能源学;生态环境科学;材料科学

Li, Yuqing^1 ; Tian, Juan^1

School of Electronic and Electrical Engineering, Bengbu University, Anhui Bengbu

233030, China^1

关键词: Density functional theory methods;    First-principles calculation;    First-principles study;    Generalized gradient approximations;    Mechanically stable;    Orthorhombic structures;    Structural parameter;    Ultrasoft pseudopotentials;   

Others  :  https://iopscience.iop.org/article/10.1088/1755-1315/94/1/012177/pdf
DOI  :  10.1088/1755-1315/94/1/012177

来源: IOP

【 摘 要 】

An orthorhombic structure boron nitride (O-BN, space group: Pbam) was studied by first-principles calculations. The structural, elastic properties, Possion's ratio, elastic anisotropy, hardness, wave velocity and Debye temperature of O-BN were investigated by density functional theory method with the ultrasoft pseudopotential scheme in the frame of the generalized gradient approximation (GGA). The results for the equilibrium structural parameters of O-BN, c-BN and w-BN are consistent with experimental values and other theoretical results. It is found that O-BN has a bulk modulus of 365 GPa, a shear modulus of 362 GPa, a Young's modulus of 816 GPa, the hardness of 59.2 GPa, a large Debye temperature 1842 K and a small Possion's ratio 0.13 under zero temperature and zero pressure; O-BN has elastic anisotropy, and shear anisotropy of shear plane {100}, {010} and {001} increases with the increase of pressures. When the pressure increases, the compression along the b-axis is much larger than those along the a-axis and b-axis in the basal plane, and the compression along the c-axis is the smallest; O-BN can satisfy the criteria for mechanical stability of orthorhombic phase, so it is mechanically stable.