Phase-transition mechanism of h -BN →→w-BN from first principles

We present ab initio   calculations of the electron energy-loss near edge structure (ELNES) on hexagonal boron nitride to reveal the mechanism of its high pressure transition to wurtzite phase. Our simulated ELNES with the proposed phase-transition path of a 1/8 shift along [0001] for N atoms in hh-BN is in excellent agreement with experimental data. Subsequent enthalpy calculation further confirmed the validity of this transition path. Our results support the experimental suggestion by Meng et al. [Y. Meng, H.-K. Mao, P.J. Eng, T.P. Trainor, M. Newville, M.Y. Hu, C.-c. Kao, J.F. Shu, D. Hausermann, R.J. Hemley, Nature Mater. 3 (2004) 111].