Anion substitution and influence of sulfur on the crystal structures, phase transitions, and electronic properties of mixed TiO₂/TiS₂ compounds

Abstract

Recent studies of TiO2/TiS2 nanostructures with various morphologies have been reported, usually showing improved properties with applications from electronics and catalysis to solar cells and medicine. However, there is a limited number of studies on the crystal structures of TiO2/TiS2 compounds with corresponding properties. In this research, relevant crystal structures of TiO1–x S x (x = 0, 0.25, 0.5, 0.75 and 1) solid solutions were investigated using an ab initio method. For each composition, crystal structures adopting anatase, rutile and CdI2 structure type were calculated on LDA-PZ and GGA-PBE levels of theory. Novel phase transitions and predicted structures are presented, and apart from several interesting metastable structures, a very interesting pressure-induced phase transition is found in the TiOS compound. Furthermore, electronic properties were studied through the dependence of semiconducting properties on dopant concentration. The first description of the electronic properties of the mixed TiO1–x S x compounds in crystal form has been presented, followed by a detailed study of the structure–property relationship, which will possibly have numerous industrial and technological applications.

Crystal-Structure Prediction and Experimental Investigation of the Polymorphic Lanthanum Fluoride Selenides LaFSe and La2F4Se

“…Density functional theory calculations were utilized in the present study using the local density approximation (LDA) with the correlation functional by Perdew and Zunger (PZ) and the generalized gradient approximation (GGA) with the PBE (Perdew, Burke, and Ernzerhof) functional . In addition, the hybrid HSE06 (Heyd–Scuseria–Ernzerhof) exchange–correlation functional and the B3LYP functional (Becke’s three-parameter functional in combination with the correlation functional of Lee, Yang, and Parr) were used since it is useful to choose several different ab initio methods, to obtain some feeling for the quantitative validity of the results (especially in cases where no experimental data are available for comparison). ,, …”

“…49 In addition, the hybrid HSE06 (Heyd−Scuseria−Ernzerhof) exchange−correlation functional 50 and the B3LYP functional (Becke's three-parameter functional in combination with the correlation functional of Lee, Yang, and Parr) 51 were used since it is useful to choose several different ab initio methods, to obtain some feeling for the quantitative validity of the results (especially in cases where no experimental data are available for comparison). 34,52,53 2.2.3. Electronic Band-Structure Calculations.…”

Computational discovery of new modifications in scandium oxychloride (ScOCl) using a multi‐methodological approach

“…However, the coordination polyhedra around the scandium atoms are deformed octahedra connected via edges and corners, thus resembling a distorted rutile or magnesium fluoride structure as far as the arrangement of the octahedra is concerned. [84][85][86] Inside the octahedra, scandium is coordinated by three oxygen and three chlorine atoms. Thermodynamically, the γ-ScOCl modification is metastable with respect to the α and β phase, at low and high pressures, respectively.…”

“…84) space group (Table 1), making it similar to the β‐phase in this regard. However, the coordination polyhedra around the scandium atoms are deformed octahedra connected via edges and corners, thus resembling a distorted rutile or magnesium fluoride structure as far as the arrangement of the octahedra is concerned [84–86] . Inside the octahedra, scandium is coordinated by three oxygen and three chlorine atoms.…”

Novel boron‐rich aluminum nitride advanced ceramic materials

“…Concerning the electronic properties, nitrides are one of the most explored semiconducting and ceramic materials together with sulfides, phosphides, and oxides, 2,12,70,[118][119][120][121][122][123][124] whereas recent studies use a combination of such materials. 37,39,[125][126][127][128][129][130] The present study focus on the boron-rich aluminum nitride semiconductors. The results obtained with the hybrid (B3LYP) functional concur the best with previous experimental and theoretical results in the AlN-BN system.…”