Density functional study of elastic and thermal properties of cubic mercury-zinc-chalcogenide ternary alloys
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Bull Mater Sci (2020) 43:268 https://doi.org/10.1007/s12034-020-02236-x
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Density functional study of elastic and thermal properties of cubic mercury-zinc-chalcogenide ternary alloys MANISH DEBBARMA1, SUBHENDU DAS1,2, BIMAL DEBNATH1, DEBANKITA GHOSH1, SAYANTIKA CHANDA1, RAHUL BHATTACHARJEE1,3 and SURYA CHATTOPADHYAYA1,* 1
Department of Physics, Tripura University, Suryamaninagar 799022, India Department of Physics, D. D. M. College, Khowai 799202, India 3 Department of Physics, Women’s College, Agartala 799001, India *Author for correspondence ([email protected]) 2
MS received 25 February 2020; accepted 1 April 2020 Abstract. First principle calculations of elastic and thermal properties of zinc-blende specimens within HgxZn1–xS, HgxZn1-xSe and HgxZn1-xTe ternary systems are executed. Elastic stiffness constants decrease non-linearly with increasing Hg-concentration in each system. Each cubic sample is mechanically and dynamically stable, elastically anisotropic, compressible against elastic deformation, ductile and fairly plastic. Hardness of specimens in each system reduces with enhancement in Hg-composition. Mixed kind of bonding with dominancy of covalent over ionic in most cases, bond bending over stretching and central type of interatomic bonding forces are calculated. In each system, covalency, Debye temperature and frequency, Debye temperature for acoustic phonon, thermal conductivity and melting temperature of specimens decreases, while Philip ionicity and Gruneisen parameter increases with enhancing Hg-concentration. Keywords. Mercury-zinc-chalcogenide ternary alloys; DFT; FP-LAPW; WC-GGA; elastic and thermal properties; Hgconcentration dependence of calculated properties.
1.
Introduction
During the past several decades, a great deal of attention has been devoted to the study of various properties of group IIB–VIA diatomic zinc chalcogenides and mercury chalcogenides, but most of the interesting characteristics of the latter are completely diverse from other IIB–VIA semiconductors. The ambient phases of Zn-chalcogenides are either wurtzite (B4) or zinc blende (B3) [1], while the latter is one of the stable phases of Hg-chalcogenides [2–4]. Wide direct band gap Zn-chalcogenide semiconductors have diverse applications in infrared spectroscopy, fibreoptics, optical memory devices, photovoltaic devices, thinfilm transistors, solid state laser devices, THz emitters, detectors and imaging systems [5–8]. Experiments have created controversy regarding inverted types of electronic band structures and negative/zero/narrow positive band gaps of diatomic Hg-chalcogenides [9–14]. They are technologically important materials in synthesizing nanostructures [15–19], in fabricating infrared (IR) detectors, lasers, thermoelectric devices, photovoltaic and solar cells [20–25]. In some important experimental studies, elastic and thermal properties of ZnS, ZnSe and ZnTe [26–31] as well as HgS, HgSe and HgTe [32–36] were investigated. Elastic
constants for ZnS, ZnSe
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