A DFT Study of Structural and Electronic Properties of ZnS Polymorphs and its Pressure‐Induced Phase Transitions

Abstract

A systematic first‐principles investigation, by using the density functional formalism with the nonlocal B3LYP approximation including a long‐range dispersion correction, has been performed to calculate the structural and electronic properties and phase transitions under pressure of the three phases of ZnS (cubic zinc blende, ZB, hexagonal wurtzite, W, and cubic rock salt, RS). Numerical and analytical fittings have been carried out to determine the equilibrium unit cell geometry and equation of state parameters for the ZnS phases. The band structures, energy gap, density of states, and vibrational frequencies and their pressure dependences are investigated. The present results illustrate that both phases, W and ZB, present very similar enthalpy and the RS phase becomes thermodynamically more stable than ZB and W structures at 15.0 and 15.5 GPa, respectively. These phase transitions are accompanied by an increase of the first shell coordination number of Zn atom and by a cell volume collapse of 13.9% and 14.3% for ZB and W phases, respectively. The atomic contributions of the conduction and valence bands, as well the binding energy for the Zn 3d orbital have been obtained.

An experimental and theoretical investigation on the optical and photocatalytic properties of ZnS nanoparticles

“…Furthermore, the effect of water on crystallinity enhancement as well as on the structure transformation of ZnS NPs at room temperature has been reported in other theoretical studies [55][56][57]. More recently, we reported the growth mechanism of ZnS NPs [4], and a DFT study of the structural and electronic properties of ZnS polymorphs and their pressure-induced phase transitions [51].…”

“…At this stage, however, it is important to note that direct comparison of theoretical and experimental results is essential and necessary to provide in depth understanding of the electronic and structural properties of NPs and their dependence on the synthetic route and environmental growth conditions. Theoretical calculations can be used not only for interpretation of experiments, but also for prediction of important aspects of new properties that emerge at the nanoscale [51,86,87]. The morphology, surface DOS, and surface Fermi level position (and the reliability of the theory to predict these) is key for explaining the physical and chemical behavior at the molecular level, because there is a high surface-to-bulk ratio and these effects are capable of governing the optical, electronic, and photocatalytic properties [86,87].…”

“…Electronic and structural properties of the ZnS NPs as well as their surfaces can be revealed straightforwardly by means of theoretical calculations and have been studied extensively in the literature [51][52][53][54][55][56][57]. For instance, Barnard et al [52] reported the theoretical equilibrium morphologies of the ZnS NPs in the wurtzite (WZ) phase as a function of size, as determined by DFT calculations.…”

Zinc blende versus wurtzite ZnS nanoparticles: control of the phase and optical properties by tetrabutylammonium hydroxide

“…6,7 ZnS can adopt three phases: cubic zinc blende, hexagonal wurtzite or the rarely observed cubic rock salt. 8 The cubic zinc blende structure of ZnS is the most stable form in the bulk which transforms into a hexagonal wurtzite structure at 1020 1C and melts at 1650 1C and both ZnS polymorphs have industrial applications. 9,10 In both cubic and hexagonal structures, Zn and S atoms are tetrahedrally bonded where the only difference is in the stacking sequence of atomic layers.…”

Improved photoluminescence emission and gas sensor properties of ZnO thin films

“…MR spectroscopy was employed to gain insight into the shortrange structural differences of the ZnO thin films (i.e., CF and PF). From group theory, the hexagonal wurtzite-type structure belongs to the space group P6 3 mc ( C v 6 4 ) with two formula units in the primitive unit cell (Z¼ 2) and has six optical modes, according to the irreducible representation: [51][52][53][54][55][56]…”