Prediction study of structural, electronic and optical properties of XIn2S4 (X=Hg, Zn) thiospinels under pressure effect

• Published in: Journal of alloys and compounds 2014-03, Vol.589, p.353-363
• Main Authors: Yousaf, Masood, Inam, F., Khenata, R., Murtaza, G., Isa, A.R.M., Saeed, M.A.
• Format: Article
• Language: English
• Subjects: Ab initio calculations; Band-structure; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electron density of states and band structure of crystalline solids; Electron states; Exact sciences and technology; Optical constants: refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity; Optical properties; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of bulk materials and thin films; Physics; Semiconductor compounds; Semiconductors
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2013.11.186

•Pressure effect is employed for the first time on HgIn2S4 and ZnIn2S4 thiospinels.•A number of physical parameters are calculated and equations are developed.•FP-LAPW+lo method is coupled with different approximations (GGA+U and mBJ-GGA).•Relationships between pressure and parameters are in accordance with the theory.•Computed band gap values have good agreement with the experimental values. First principle calculations are carried out to study the effect of pressure (up to 30GPa) on physical properties of HgIn2S4 and ZnIn2S4 thiospinels. A number of structural, electronic and optical parameters are calculated, and equations are developed for their prediction at different pressures. Highly effective all electron FP-LAPW+lo method coupled with two different approximations (GGA+U and mBJ-GGA) provides very accurate results. All relationships developed between pressure and structural parameters are in full accordance with the established theory thus validating the approach used in the current study. Computed In–S bond length for ZnIn2S4 matches closely with the experimental value. The band gap values of 0.920eV (1.851eV) and 1.68eV (2.733eV) are obtained with GGA+U (mBJ-GGA) at 0GPa for HgIn2S4 and ZnIn2S4, respectively. Additionally, we have calculated the optical properties, namely, the complex dielectric function, refractive index, extinction coefficient, reflectivity, optical conductivity, absorption coefficient and electron energy loss function under pressure effect for radiation up to 30.0eV. The first critical point also known as optical’s absorption edge calculated with GGA+U (mBJ-GGA) appears at 0.939eV (1.891eV) and 1.701eV (2.981eV) for HgIn2S4 and ZnIn2S4, respectively. Variation of the absorption spectrum indicates the prospective use of both compounds for device applications, which can be operated on a wide range of the energy scale. The entire work gives useful results of fundamental importance, which can be utilized for the fabrication of optoelectronic devices.