Pnma-BN: Another Boron Nitride Polymorph with Interesting Physical Properties
AbstractStructural, mechanical, electronic properties, and stability of boron nitride (BN) in Pnma structure were studied using first-principles calculations by Cambridge Serial Total Energy Package (CASTEP) plane-wave code, and the calculations were performed with the local density approximation and generalized gradient approximation in the form of Perdew–Burke–Ernzerhof. This BN, called Pnma-BN, contains four boron atoms and four nitrogen atoms buckled through sp3-hybridized bonds in an orthorhombic symmetry unit cell with Space group of Pnma. Pnma-BN is energetically stable, mechanically stable, and dynamically stable at ambient pressure and high pressure. The calculated Pugh ratio and Poisson’s ratio revealed that Pnma-BN is brittle, and Pnma-BN is found to turn brittle to ductile (~94 GPa) in this pressure range. It shows a higher mechanical anisotropy in Poisson’s ratio, shear modulus, Young’s modulus, and the universal elastic anisotropy index AU. Band structure calculations indicate that Pnma-BN is an insulator with indirect band gap of 7.18 eV. The most extraordinary thing is that the band gap increases first and then decreases with the increase of pressure from 0 to 60 GPa, and from 60 to 100 GPa, the band gap increases first and then decreases again. View Full-Text
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Ma, Z.; Han, Z.; Liu, X.; Yu, X.; Wang, D.; Tian, Y. Pnma-BN: Another Boron Nitride Polymorph with Interesting Physical Properties. Nanomaterials 2017, 7, 3.
Ma Z, Han Z, Liu X, Yu X, Wang D, Tian Y. Pnma-BN: Another Boron Nitride Polymorph with Interesting Physical Properties. Nanomaterials. 2017; 7(1):3.Chicago/Turabian Style
Ma, Zhenyang; Han, Zheng; Liu, Xuhong; Yu, Xinhai; Wang, Dayun; Tian, Yi. 2017. "Pnma-BN: Another Boron Nitride Polymorph with Interesting Physical Properties." Nanomaterials 7, no. 1: 3.
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