Structural and electronic properties of La-doped CaTiO3 crystal

There is experimental and ccmputational evidence that some important properties such as electrical conductivity and ferroelectricity in the CaTiO3 crystal change according to the dopant states. Using an INDO quantum-chemical computational method modified for crystal calculations we explore the stability of the La-doped CaTiO3 Crystal in both phases, cubic and orthorhombic. The calculations are carried out by means of the supercell model based on the LUC (large unit cell) approach as it is implemented into the CLUSTERD computer code. The equilibrium geometry for impurity is found together with the crystalline lattice distortions. Atomic displacements and relaxation energies are analyzed in a comparative manner for the two crystallographic phases. A new effect of electron transfer from the local one-electron energy level within the band-gap to the conduction band is observed. (C) 2002 Wiley Periodicals, Inc.