Li-doping effect on the energy structure of KTaO3

The electronic structure calculation of pure and Li doped potassium tantala te KTaO3 (KTO) is performed by first-principle CASTEP code ([1]) and INDO ( Semiempirical Hatree-Fock;) methods. In ab initio calculations (CASTEP) bas ed on density Functional theory (DFT) the plane wave (PW) basis and ab init io pseudopotentials have been used. DFT method was applied to define the of f-center displacement of Li+ ions, substituted for K+ in KTO and displaceme nts of nearest neighboring O2- ions. These DFT calculations have been made for supercell included 2x2x2 primitive cells of KTO. To investigate the ele ctronic structure of KTaO3:Li(KTL) near the top of the valence band and the bottom of the conduction band the supercell 4x4x4 and INDO methods were us ed. Two split local states at the top of the valence band of KTL have been found. The origin of these levels is related with the small displacements O 2- ions situated nearby with Li off centers.