Electronic, magnetic and dielectric properties of multiferroic MnTiO₃

Abstract

The ground-state structural, electronic, magnetic, optical and dielectric properties of MnTiO₃ are 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 MnTiO₃ has an indirect band gap of 0.85 eV. The calculated local magnetic moment of Mn ion is 4.19 μ[sub 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 μC/cm². B-site Ti ions in 3 d⁰ state dominate ferroelectric polarization of multiferroic MnTiO₃, whereas A-site Mn ions having partially filled 3 d⁵ orbitals are considered to contribute to its antiferromagnetic properties. Furthermore, it is predicted that multiferroic MnTiO₃ shows good dielectric and optical properties.