Structural and electronic properties of La‐doped CaTiO₃ crystal

Abstract

ABSTRACT:There is experimental and computational evidence that some important properties such as electrical conductivity and ferroelectricity in the CaTiO 3 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 CaTiO 3 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.

A quantum mechanical study of La-doped Pb(Zr,Ti)O3

“…SrTiO 3 , BaTiO 3 and CaTiO 3 containing diverse point defects. Some examples include La-, Na-and Nb-doped SrTiO 3 [24][25][26][27], La-, Nb-, Al-and Sc-modified BaTiO 3 [28][29][30][31], La-and Nb-doped CaTiO 3 [32][33][34] and different electronic defects in titanates [35][36][37][38][39][40].…”

Structural and electronic effects of an Nb impurity in PZT crystals

“…Note that this model has previously been applied to study defects in other titanates. Some recent examples include calculation of oxygen-vacancy defects in ferroelectric BaTiO 3 bulk [7] and surface [8], SrTiO 3 bulk [9] and different surfaces [10,11], as well as PbTiO 3 structures [12], investigation of Al-and Sc-impurities in BaTiO 3 [13], La impurity doping in SrTiO 3 [14,15], BaTiO 3 [16] and CaTiO 3 [17] crystals, Nb impurity in SrTiO 3 [18], CaTiO 3 [19] and BaTiO 3 [20] lattices, and, finally, a study of H atom incorporation in BaTiO 3 [21,22] and CaTiO 3 [23] crystals.…”