Research Information System
Thesis Type: Postgraduate
Institution Of The Thesis: Gazi University, Fen Bilimleri Enstitüsü, Turkey
Approval Date: 2023
Thesis Language: Turkish
Student: ZEYNEP KIZILIRMAK
Supervisor: Şule Uğur
Abstract:
In this thesis, structural, electronic, elastic, phonon, thermodynamic and optical properties of XIn2S4 (X = Mg, Zn, Cd) spinel compounds were studied. The calculations were performed using two approximations to density functional theory (DFT), namely, the local density approximation (YYY) and the generalized gradient approximation (GGA). The linear tetrahedron (LT) method and the Methfessel–Paxton (MP) method were used in all calculations. Electronic band structure calculations show that the ZnIn2S4 and CdIn2S4 are an indirect band gap materials, whereas MgIn2S4 shows direct electronic band gap. The elastic calculations reveal that these compounds are ductile materials. The speed of sound and Debye temperature of these compounds has been estimated from the elastic constants. The calculated values are in reasonable agreement with theoretical data. Temperature dependence of heat capacity of studied compounds exhibit identical characteristics of typical solids. Calculated phonon dispersion illustrates that the XIn2S4 (X = Mg, Zn, Cd) compounds are stable in the cubic spinel structure.
Key Words : Spinel compound, Electronic band structure, Elastic constants, Phonon
dispersion