Analysis of the structural, electronic, elastic and thermodynamic properties of CuAl2X4 (X = O, S) spinel structure

• Published in: Materials research bulletin Vol. 108; pp. 255 - 265
• Main Authors: Obeid, Mohammed M., Mogulkoc, Y., Edrees, Shaker J., Ciftci, Y.O., Shukur, Majid M., Al-Marzooqee, M.M. Hussein
• Format: Journal Article
• Language: English
• Published: United States Elsevier Ltd 01.12.2018
• Subjects: ALUMINATES; APPROXIMATIONS; CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; COPPER COMPOUNDS; DENSITY FUNCTIONAL METHOD; Density functional theory; Elastic constants; Electronic properties; EXPERIMENTAL DATA; GROUND STATES; LATTICE PARAMETERS; MECHANICAL PROPERTIES; PHASE TRANSFORMATIONS; PRESSURE DEPENDENCE; SEMICONDUCTOR MATERIALS; Spinel structure; SPINELS; SULFUR COMPOUNDS; SYMMETRY; TEMPERATURE DEPENDENCE; THERMODYNAMIC PROPERTIES; Density functional theory; Electronic properties; Elastic constants; Thermodynamic properties; Spinel structure
• ISSN: 0025-5408; 1873-4227
• DOI: 10.1016/j.materresbull.2018.09.013

Energy versus primitive unit cell volume of CuAl2X4 (X = O, S) spinel structures. [Display omitted] •Fundamental properties of CuAl2X4 (X = O, S) aluminate spinels have been investigated.•The pressure dependence of the elastic constants Cij can be successfully fit by a straight line.•CuAl2X4 (X = O, S) compounds are mechanically stable at ambient conditions.•Temperature and pressure dependences of some macroscopic parameters are achieved. The structural, electronic, elastic and thermodynamic properties of oxo- and thio-spinels have been predicted based on the ultrasoft pseudo-potential scheme as implemented in the CASTEP code. The exchange-correlation potential was treated within the generalized gradient approximation (GGA-PBE). The calculated structural parameters such as lattice constants and internal parameters are in good agreement with the available experimental data. The ground state electronic band structure revealed that CuAl2X4 (XO, S) spinels are direct band gap semiconductors with a transition along Г-Г symmetry points. The calculated values of elastic constants satisfy the Born criteria at ambient conditions and confirm that the spinel structures of CuAl2O4 and CuAl2S4 are mechanically stable. The thiospinel structure may have a phase transition under pressure, due to the negative value of C44. The influence of temperature and pressure on macroscopic characteristics of CuAl2O4 and CuAl2S4 compounds was estimated using the quasi-harmonic Debye model.