First principles investigations of HgX (X=S, Se and Te)

Abstract

Purpose: The aim of this study is to determine the structural, and mechanical properties of Hg chalcogenide materials (HgX; X=S, Se, Te) in the zinc-blende structure which are presented as promising candidates for modern optoelectronic and spintronic applications. The dependence of elastic constants of pressure for three materials are evaluated. Moreover, isotropic mechanical properties such as bulk modulus, shear modulus, Young's modulus and Poisson's ratio are obtained.Design/methodology/approach: First principles calculations based on Density Functional Theory are performed by employing Projector Augmented Waves potentials. The electronic exchange and correlation function is treated by using Generalized Gradient Approximation parametrized by Perdew, Burke and Ernzerhof (PBE96).Findings: Calculated results of structural and mechanical properties are in good agreement with those of experimental and other theoretical studies. This three materials in zinc-blende structure are mechanically stable. İsotropic mechanical properties are also obtained. Resistance against both linear strain and shear strain and ductility decrease as we go into the sequence of HgS−>HgSe−>HgTe. The wave velocities and Debye temperatures calculated for this materials. Debye temperatures are founded for HgS, HgSe and HgTe as 306. 21 K, 264.30 K and 240.19 K, respectively Research limitations/implications: Calculation speeds of the computers and data storage are some limitations. Also, the lack of experimental data hinder for the comparison of our results.Practical implications: Obtaining high pressure elastic constants by calculations is preferable since it is very difficult or even impossible to measure them by experimentally.Originality/value: There are only restricted number of investigation of elastic constants of mercury chalcogenides both theoretically and experimentally.

Effect of Pressure on Interband and Intraband Transition of Mercury Chalcogenide Quantum Dots

“…Following the shift of the reflections with pressure in the zinc blende phase, we extract a pressure coefficient of the lattice parameter of ⁄ = -6.4x10 -3 nm/GPa around the smallest probed pressure of 1 GPa and average lattice parameter ≃ 0.645 nm, see Figure 2b and c. This corresponds to a bulk modulus at zero pressure = − /(3 / ) ≃33 GPa, very close to the value of 34 GPa expected for bulk HgTe. 38 Assuming a Poisson coefficient of 0.288, 38 we can estimate the experimental Young modulus to be 42 GPa, again very close to the value of 40 GPa commonly admitted for bulk HgTe. 39 We observe that the bulk modulus significantly decreases with pressure, with an amplitude of 21 GPa around 3 GPa pressure, a signature of the beginning of the transition towards the cinnabar phase.…”

Mercury Chalcogenide Quantum Dots: Material Perspective for Device Integration

“…By fitting the shift of the diffraction peak in the zinc blende phase (Figure 20b and c), the change in the lattice parameter can be estimated to be 10 pm/GPa, corresponding to a bulk modulus for HgTe NCs of 33 GPa. The same value holds for HgTe NPLs 62 and corresponds to the bulk value, 251 suggesting that the ligands do not considerably influence the mechanical properties of the NC film.…”

The Strong Confinement Regime in HgTe Two-Dimensional Nanoplatelets

“…This value is similar to the one measured for the HgTe NCs 47 (33 GPa) which was relatively close to the one of the bulk (34 GPa). 48 The confinement energy appears to be dependent on the applied pressure, see Figure 4b-c, 6c and S10. The confinement energy gradually increases with pressure corresponding to a positive value for dEG/dP.…”