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Effects of Hydrostatic Pressure and Biaxial Strains on the Elastic, Electronic and Lattice Vibrational Properties of Trigonal Boron Nitride
Author(s) -
Li Shuaiqi,
Shi Liwei,
Zhu Haiyan,
Xia Wangsuo,
Wang Ying
Publication year - 2019
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.201800699
Subject(s) - materials science , boron nitride , debye model , hydrostatic pressure , condensed matter physics , band gap , lattice constant , elastic modulus , anisotropy , phonon , raman spectroscopy , composite material , thermodynamics , optics , diffraction , physics , optoelectronics
The effects of hydrostatic pressure and biaxial strains on the elastic, electronic, and lattice vibrational properties of a new superhard material trigonal boron nitride ( T ‐BN) are studied by first‐principles calculation. The mechanical and dynamical stabilities of T ‐BN are confirmed by elastic constants criteria and phonon dispersion curves. It is found that all elastic constants and elastic modulus increase (decrease) under pressure and compressive (tensile) strainϵ x x. The Vicker's hardness of every single chemical bond as well as the crystal is calculated by a microscopic model. The hardness of T ‐BN 55.5 GPa is smaller than that in c ‐BN (64 GPa) but increases significantly with increasing pressure and compressiveϵ x x. The anisotropic index and anisotropic velocities, as well as the Debye temperature for T ‐BN are also discussed. Moreover, the computational infrared absorption spectra exhibit significant blueshift under pressure and − 5 % < ϵ x x < 3 % , while redshift of A 3 and E 4 modes can be observed whenϵ x x > 3 % . Electronic calculation shows the T ‐BN is an indirect band‐gap semiconductor, and energy gap decreases monotonically under computational conditions. Analysis based on density of states is conducted, clarifying the causes of bonding and bandgap changes in T ‐BN.