First-Principles Calculation of the Structural, Elastic, Electronic and Lattice Dynamics of GeTiO₃

Abstract

The properties of cubic (Pm3m, 221 space group) GeTiO₃were investigated via the first principles method implemented in CASTEP computer code. The elastic constant results show that GeTiO₃is mechanically stable in a cubic phase. The electronic properties indicate hybridizations among the O anion at the 2p orbital, Ge cation at the 4s orbital, and Ti at the 3d orbital, with an indirect band gap at the X-R point. The lattice dynamics of GeTiO₃shows the strength of the existing covalent Ge-O and Ti-O bonding. Results also reveal that O 2p, Ge 4s, and Ti 3d states play an important role in the instability of the perovskite oxide of and in providing a stable rhombohedral (R3m) structure compared with a tetragonal structure (P4mm), the former of which refers to the imaginary dispersion in the phonon structure and relative energy calculation.

Keywords:

• Density functional theory
• elastic constant, electronic properties
• lattice dynamics

Acknowledgments

This study was supported by the Fundamental Research Grant Scheme by the Ministry of Higher Education and the Research Management Institute (RMI) of the Universiti Teknologi MARA Malaysia.