A first-principles study of structure, elastic and electronic properties of GeTiO₃ as environmentally innocuous ferroelectric perovskites

The structural parameters, elastic properties, spontaneous polarization, electronic band structure, and density of states (DOS) of GeTiO₃ in tetragonal phase have been studied computationally using pseudopotential plane-wave (PP-PW) method based on the density functional theory (DFT). The generalized gradient approximation (GGA) was used to estimate the exchange-correlation energies. The equilibrium lattice parameter, unit cell volume, bulk modulus and its derivative are obtained and compared with the available theoretical data. The elastic characteristics such as elastic constants, Poisson's ratio, elastic modulus, and anisotropy factor are obtained in the pressure range 0–50 GPa. Our computed results of elastic constant satisfy Born's stability criterion. In view of Pugh's prediction standard, the material is taken as ductile. Once the elastic constant is calculated, the Debye temperature of GeTiO₃ compound is also evaluated from the average sound velocity. The density of states, band structures, and charge-density distribution are discussed and compared with previous computational results. The calculation within Berry's phase approach indicate a high spontaneous polarization of tetragonal GeTiO₃ (1.125 C/m²). Thus, the substance is identified as a promising environmentally friendly ferroelectric material. (author)