Semiconductor Physics, Quantum Electronics & Optoelectronics, 28 (4), P. 424–431 (2025).
DOI: https://doi.org/10.15407/spqeo28.04.424
Distribution of Mg and Ti atoms over octahedral sites and physical properties of Mg2TiO4
N.I. Kashirina1*, L.V. Borkovska1, Ya.O. Kashyrina2, O.S. Muratov3, O.S. Roik3
1V. Lashkaryov Institute of Semiconductor Physics, NAS of Ukraine, 41 Nauky Avenue, 03028 Kyiv, Ukraine
2Frantsevich Institute for Problems of Materials Science, NAS of Ukraine, 3 Omelyan Pritsak Street, 03142 Kyiv, Ukraine
3Taras Shevchenko National University of Kyiv, Faculty of Chemistry, 12 Hetmana Pavla Skoropadskoho Street, 01033 Kyiv, Ukraine
*Corresponding author e-mail: kashirina1506@gmail.com
Abstract. Ceramics based on Mg2TiO4 (MTO) are widely used in numerous modern quantum electronic devices. The present paper deals with a study of cubic and tetragonal modifications of MTO. The band gap and electron state density of the cubic MTO are calculated for different distributions of Mg and Ti atoms over octahedral positions in the unit cell. Both random distributions of atoms over the octahedral positions and highly symmetric combinations are considered. The band gap as a function of the total energy of the unit cell is constructed. The band gap width increases at decreasing the free energy of a crystal. The highly symmetric distribution of atoms over the octahedral positions is shown to lead to a transition from cubic MTO to tetragonal syngony with a lower energy compared to an MTO cubic crystal with a random distribution of atoms over the octahedral positions. The band gap width for the cubic Mg2TiO4 with a random distribution of Mg and Ti atoms over the octahedral positions calculated by us using Vienna Ab initio Simulation Package (VASP) was 4.086 eV. The obtained results are in a good agreement with experimental data. The calculated band gap width for tetragonal MTO was 4.988 eV.
Keywords: Mg2TiO4, inverse spinel, VASP, band structure calculation, density of states.
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