First principles study of structural and electronic properties of Ce substituted Ti2O3 slabs with compositions TixCe4-xO6 where x = 0, 1, 2, 3, 4

Abstract

This study employs Density-functional theory (DFT) to investigate the structural and electronic properties of Ce2O3–Ti2O3 alloys. We systematically examined the structural and electronic properties of the two dimensional (2D) alloys, thereby exploring the impact of Ce substitution in Ti2O3 in full alloy range. The study of charge transfer and bonding analysis revealed the series of materials have dominant ionic character and it decreases linearly with an increase of Ce percentage. Initially, we observed that the parent material Ti2O3 exhibited semiconducting behavior with a narrow band gap of 0.29 eV. However, upon further incorporating Ce substitution into the pristine crystal structure, all the prepared alloys showed an increase of population of states in the band structure. Notably, the band gap of Ti3CeO6 alloy decreased to 0.13 eV and eventually reduced to zero. This trend was consistent across other metallic alloy systems, including Ti2Ce2O6, TiCe3O6, Ce2O3. Moreover, our results revealed that an increased concentration of Ce atoms led to the emergence of magnetic behaviour in the alloys. The work function of all materials to check the reactivity of the studied alloys is also reported. Further, the DFT + U method is employed to include the Hubbard U correction for electronic properties of materials.