Phase transition properties of YbN under pressure

Abstract

In the present paper, we have investigated the phase transition properties of Ytterbium nitride (YbN) under high pressure by using the full potential linear augmented plane wave plus local orbitals approach within the framework of density functional theory as implanted in the WIEN2k package. In this approach the generalized gradient approximation (GGA) is chosen for the exchange-correlation functional energy optimization for calculating the total energy. At ambient conditions YbN stabilize in NaCl (B1 phase) structure characterized by the space group Fm-3m. Under compression, it undergoes first-order structural transition from Fm-3m to Pm-3m (B2) phase at 51.73 GPa. On further increasing pressure it goes to body centred tetragonal (BCT) phase at 79.56 GPa. Under ambient conditions, the energy in B1 phase is found to be lower than that of B2 phase. At high pressures beyond B1 to B2 phase transition, the energy of B2 phase is found to be slightly lower than that in B1 phase. The structural properties viz., equilibrium lattice constants, bulk modulus, its pressure derivative and total energy are calculated in four different phases i.e. B1, B2, B3 (zinc blende), and BCT phases and compared with previous calculations and available experimental data.