First Principles Calculations for Valence States of Mn in SrTiO3

Abstract

The valence change mechanism of doped Mn in SrTiO₃ has been discussed on the basis of the first-principles calculation results. These results show that the crystal with Mn²⁺ is stabilized by a peculiar tilting deformation of the MnO₆ octahedron, whereas the crystal with Mn⁴⁺ does not exhibit such tilting. The valence of Mn is closely related to the lattice deformation, and the experimentally observed change in the valence of Mn in SrTiO₃ can be well explained by the thermal excitations of the tilting modes of MnO₆.