High pressure-induced phase transitions in AgI semiconducting compound up to 1 Mbar

Atomistic study of stability and new phase transitions of zinc selenide using FP-LMTO-PLW method

“…Recently, Structural, thermoelastic, and mechanicalproperties of ZnX (X = O, S and Se) in wurtzite and zinc blende phase have been studied by Valdez et al [5] using SIESTA code. The investigation of physical properties of the binary compounds under hydrostatic pressure has been an active topic of researches in condensed matter physics over the previous decades [6][7][8]. Withthis background, the presentpapergives a detailedstudy on the structural properties and energy band gap of ZnSe and compares theseresultswithothersexperimental and theoriacl data.…”

“…In the presentwork, the structural parameters of ZnSesemiconducting compound wereobtainedfrom E(V) (Fig 1), for each of the eight structures consideredhere: NaCl (B1), CsCl (B2), ZnS (B3),Wurtzite (B4), NaTl (B32), and WC (Bh). The equilibrium lattice constant a0, bulk modulus B0 and pressure derivative of bulk modulus B0 ' have been computed by minimizing the total energy by means of Murnaghan's equation of state (EOS) [13] (For more details, please see our previous works [6,8]). Total energy versus volume data for the rocksalt, CsCl, zincblende, wurtzite, NiAs, NiAs, NaTi and WC structures of ZnSe crystal shown in Fig.…”

“…The stability of any particular structure corresponds to the lowest Gibbs free energy, which is given by G = E+ PV-TS, where E is the internal energy, S is the vibrational entropy, P is the pressure, and V is the volume [6,8]. Since our calculations were performed at T = 0 K, the Gibbs free energy G is then equivalent to the enthalpy H = E + PV and the pressure Pt for which Gibbs energies of two phases are equal is defined as the transition between these two phases [6,8].…”