Structural, electronic, and mechanical properties of cubic TiO₂: A first-principles study

Abstract

We present an analysis of structural, electronic, and mechanical properties of cubic titanium dioxide (TiO 2 ) using an all electron orthogonalzed linear combinations of atomic orbitals (OLCAO) basis set under the framework of density functional theory (DFT). The structural property, especially the lattice constant a, and the electronic properties such as the band diagram and density of states (DOS) are studied and analyzed. The mechanical properties such as bulk moduli, shear moduli, Young's Moduli, and Poison's ratio are also investigated thoroughly. The calculations are carried out on shear moduli and anisotropy factor for cubic TiO 2 . The Vickers hardness is also tested for fluorite and pyrite cubic-structured TiO 2 . Furthermore, the results are compared with the previous theoretical and experimental results. It is found that DFTbased simulation produces results which are approximation to experimental results, whereas the calculated elastic constants are better than the previous theoretical and experimental values.

Comparative study on structural, electronic, optical and mechanical properties of normal and high pressure phases titanium dioxide using DFT

“…From the comparision, we can find that lattice constant for anatase and rutile vary only by 0.4% from experimental data [39] whereas it shows 1.3% variation with experimental data for fluorite [11]. However results are much better than the theoretical data [6,25,33,34]. Bandgap values calculated using OLCAO-GGA-PBE-SOL for all the phases of TiO 2 are consistent with other theoretical data but underestimated compared to experimental data [30].…”

“…Anatase and rutile belogs to tetragonal crystal system whereas fluorite and pyrite belongs to cubic crystal system. Anatase [29], rutile [39] and fluorite [11] TiO 2 structures are created using experimental lattice parameters and wyckoff positions whereas for pyrite the lattice constants considered are a=b=c=4.844 Å [25]. Structure has been optimized using maximized force of 0.005eV/Å and maximum step length of 0.5 Å.…”

“…Cubic TiO 2 is formed by heating anatase TiO 2 at a high temperature of about 1900-2100k under high pressure of about 48 GPa in a diamond anvil cell [23,24]. Cubic TiO 2 is the best choice for solar photovoltaic applications to extract solar energy and a healthy choice for a hazard-free environment [25].…”

“…Shatendra Sharma et al [28], calculated the electronic and optical properties for Strontium Sulphide (SrS) using LDA, GGA, and MGGA and observed that MGGA gives the bandgap value more close to experimental value while LDA and GGA gives underestimated results. Dash et al [25,29], used OLCAO-LDA-Perdew and Zunger (PZ) (1981) method to investigate various properties of anatase and cubic TiO 2 and found an improvement in mechanical properties. Coronado et al [30], also used OLCAO-GGA method to verify the experimental data with theoretical data.…”

“…Researchers have calculated the structural, elastic, electronic, optical, thermal and acoustic properties of various phases of TiO 2 theoretically [6,23,25,26,29,[31][32][33][34][35][36][37][38] as well as experimentally [11,30,[39][40][41][42]. Zhang et al [43], analyzed the photocatalytic activity among natural phases of TiO 2 based on the comparison of effective masses for these polymorphs and found that anatase is having higher photocatalytic activity than other two polymorphs.…”