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Elastic anisotropy and thermodynamic properties of tetrahedrally bonded dense C 2 N 2 (NH) under high pressure and high temperature
Author(s) -
Yan Haiyan,
Zhang Meiguang,
Wei Qun,
Guo Ping
Publication year - 2013
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.201248225
Subject(s) - debye model , thermal expansion , bulk modulus , pseudopotential , thermodynamics , heat capacity , materials science , anisotropy , shear modulus , atmospheric temperature range , ab initio , crystal (programming language) , max phases , condensed matter physics , chemistry , physics , organic chemistry , quantum mechanics , computer science , programming language , carbide , composite material
The elastic anisotropy and thermodynamic properties of the potential superhard carbon nitride phase C 2 N 2 (NH) have been investigated by using an ab initio plane‐wave pseudopotential density theory method. The crystal parameters have been calculated at ambient as well as high pressure. The Young's modulus and shear modulus as a function of crystal orientations for C 2 N 2 (NH) have been systematically investigated. The Young's modulus is found to reach a maximum along the [100] direction. Using a set of total energy versus volume obtained with the first‐principles calculations, the quasiharmonic Debye model is applied to the study of the thermal and vibrational effects. The dependence of Debye temperature, Grüneisen parameter, heat capacity, and expansion coefficient on the temperature and pressure are systematically explored in the whole pressure range from 0 to 60 GPa and temperature range from 0 to 2000 K.