High-pressure structural phase transition and electronic properties of the group-III nitrides (original) (raw)
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Indian Journal of Pure and Applied Physics
The structural, magnetic and elastic properties of the rare earth nitride YbN under hydrostatic pressure have been investigated using the Full Potential Non-orthogonal Local-Orbital minimum basis method (FPLO) using the Local Spin Density Approximation (LSDA) and Generalized Gradient Approximation (GGA). Three phase transitions are predicted from rock-salt (RS) to CsCl, zinc-blend (ZB) to CsCl, and ZB to RS at 220, 12, and-15 GPa, respectively. The half-metallic property was found only in the ZB phase, while the RS and CsCl phases show a metallic behaviour. The bulk moduli of YbN in RS, CsCl and ZB structures are calculated to be 172.8, 160, and 115.3 GPa, respectively.
Journal of Physics and Chemistry of Solids, 2007
The high-pressure structural phase transition in six transition metal mononitrides (TMNs) (M=Ti, Mo, V, Nb, Hf, and Zr), have been studied using a two-body interionic potential theory which includes the effect of Coulomb screening due to the semi-metallic nature of these compounds. The present theoretical results have been compared with the corresponding experimental and predictions of LDA theory. These TMN compounds have been found to undergo NaCl ( B 1 ) to CsCl ( B 2 ) phase transition, at a pressure quite high as compared to other binary systems. We have also predicted the elastic constants. It is shown that these binary materials are partially ionic in nature and the structural transformation is analogous to several other ionic binary systems.