Publication No.10 P. Sánchez, E. Patiño, F. Erazo, H. Pinto, A. Stashans. Computer Modelling of Impurities in Titanates. - 18th Europ. Phys. Soc. Conf., Montreux (Switzerland), 2000, p. 110. Abstract: We have used the modified for crystals advanced quantum-chemical method to study doped BaTiO3, SrTiO3 and CaTiO3. In La-doped SrTiO3 we have found that for its tetragonal lattice the relaxation of the atoms presents a rotation around the x-axis, and a larger displacement along the z-axis. Besides, we have observed the electron transfer to the conduction band, which is obviously connected with superconductivity phenomenon. Additionally, acceptor (Al, Sc) doping was studied. In La-doped BaTiO3 cubic phase the Ti atoms move away from the impurity by 0.07 Å. In the case of Nb-doping, the atomic displacements are symmetrical in both phases. In addition, it has to be noted that electron transfer to the conduction band occurs in Nb-doped material. The Nb-doped CaTiO3 crystal orthorhombic lattice shows the transition of one electron to the conduction band. This effect might justify increase of conductivity in Nb-doped material for orthorhombic phase. Some of our results explain experimentally observed and non-understood effects.
Back to the main page of our research centre