Calculations of radiation-induced point defects, polarons and excitons in ferroelectric perovskites

Abstract

We review results of our recent large-scale computer simulations of radiation-induced point defects, excitons and polarons in ABO 3 perovskite crystals, focusing mostly on KNbO 3 and KTaO 3 as representative examples. We have calculated the atomic and electronic structure of defects, their optical absorption, defect-induced electron density redistribution, and activation energies for defect migration. The majority of our results were obtained using the quantum-chemical method of the intermediate neglect of differential overlap (INDO) based on the Hartree–Fock formalism, as well as the shell model (SM). The main findings are compared with those obtained by means of ab initio density functional theory (FP-LMTO) first-principles calculations.