Electronic, magnetic and dielectric properties of multiferroic MnTiO₃

The ground-state structural, electronic, magnetic, optical and dielectric properties of MnTiO3are calculated using density functional theory within the generalized gradient approximation. The structure parameters obtained agree well with experimental results. The electronic structure results show that the G-type antiferromagnetic phase of LN-type MnTiO3has an indirect band gap of 0.85 eV. The calculated local magnetic moment of Mn ion is 4.19 ̌B. The calculated Born effective charges (BECs, denoted by tensor Z) show that the Z of Ti and O atoms are significantly and anomalously large. Interestingly, ferroelectric spontaneous polarization of large magnitude is predicted to be along [111] direction with a magnitude of 87.95-105.22 ̌C/cm2. B-site Ti ions in 3 d0state dominate ferroelectric polarization of multiferroic MnTiO3, whereas A-site Mn ions having partially filled 3 d5orbitals are considered to contribute to its antiferromagnetic properties. Furthermore, it is predicted that multiferroic MnTiO3 shows good dielectric and optical properties.