A novel large-cell boron nitride polymorph.

[Display omitted] Through density functional theory simulations, the structural properties, stability, mechanical properties, elastic anisotropy as well as electronic properties for boron nitride allotropes with cubic structure, Pn -3 n BN, are investigated in this work. Studying the phonon spectra, molecular dynamics as well as elastic constants of Pn -3 n BN, it is found that porous Pn -3 n BN is stable in dynamics, thermodynamics and mechanics. The B (bulk modulus), G (shear modulus) and E (Young's modulus) of Pn -3 n BN are 64 GPa, 26 GPa and 69 GPa, respectively. The B / G (the ratio of bulk modulus to shear modulus) and v (Poisson's ratio) of Pn -3 n BN are 2.43 and 0.319, respectively, which exhibit ductility. The three-dimensional surface construction for Young's modulus, the maximum and minimum of shear modulus, the maximum and minimum of Poisson's ratio of Pn -3 n BN are all irregular spheres, indicating that Pn -3 n BN has elastic anisotropy. The E max / E min of Pn -3 n BN displays isotropy with 1.00 in (1 1 1) plane, and is not equal to 1.00 in other principal planes, showing anisotropy. The conduction band minimum (CBM) and the valence band maximum (VBM) of Pn -3 n BN are both located at point G, and the band gap width of Pn -3 n BN is 5.197 eV, from which Pn -3 n BN is a wide band gap and direct band gap semiconductor material. [ABSTRACT FROM AUTHOR]