Structural phase transition, electronic and elastic properties in TlX (X = N, P, As) compounds: Pressure-induced effects

Using the first-principles plane-wave pesudopotential (PW-PP) method with the generalized gradient approximation (GGA) for the exchange-correlation potential, we have studied the structural, electronic and elastic properties of TlX (X = N, P, As) compounds under hydrostatic pressure. Our calculations show that TlN, TlP and TlAs undergo a phase transition from the zincblende (ZB) to the rocksalt (RS) structure at 19.05, 7.29 and 5.01 GPa, with a volume collapse of 14.96%, 17.45% and 18.03%, respectively. The influence of crystallographic structure and hydrostatic pressure on electronic band structures, elastic constants, and aggregate bulk moduli are investigated. Further, the elastic wave velocities, Debye temperatures and melting temperatures for zincblende TlN, TlP and TlAs compounds are obtained. Our calculated results are compared with the previously reported theoretical data.