R. I. Eglitis

FIRST-PRINCIPLES AND SEMIEMPIRICAL CALCULATIONS FOR BOUND-HOLE POLARONS INKNBO3

The ab initio linear muffin-tin-orbital formalism and the semiempirical method of the intermediate neglect of the differential overlap based on the Hartree-Fock formalism are combined for the study of the hole polarons ~a hole trapped nearby the cation vacancy! in a cubic phase of KNbO3 perovskite crystals. The 40-atom and 320-atom supercells were used, respectively. We predict the existence of both one-site and two-site ~molecular! polarons with close optical absorption energies ~0.9 eV and 0.95 eV!. The relevant experimental data are discussed. @S0163-1829~99!12725-5#

FIRST-PRINCIPLES AND SEMIEMPIRICAL CALCULATIONS FOR F CENTERS IN KNBO3

The linear muffin-tin-orbital method combined with density functional theory (local approximation) and the semiempirical method of the intermediate neglect of the differential overlap (INDO) based on the Hartree-Fock formalism are used for the study of the

Semiempirical Hartree-Fock calculations for pure and Li-doped KTaO3

F

First-principles calculations of the atomic and electronic structure of SrZrO3 and PbZrO3 (001) and (011) surfaces.

centers (O vacancy with two electrons) in cubic and orthorhombic ferroelectric KNbO

Charge distribution and optical properties of and F centres in crystals

_3

Correlated annealing of radiation defects in alkali halide crystals

crystals. Calculations for 39-atom supercells show that the two electrons are considerably delocalized even in the ground state of the defect. Their wave functions extend over the two Nb atoms closest to the O vacancy and over other nearby atoms. Thus, the

A comparative study of the atomic and electronic structure of F centers in ferroelectric KNbO3: Ab initio and semi-empirical calculations

F

Ab initio calculations of the atomic and electronic structure of MgF2 (011) and (111) surfaces

center in KNbO

Computer modeling of point defects, polarons, excitons, and surfaces in perovskite ferroelectrics

_3

Large-scale first-principles calculations of Fe-doped SrTiO3

resembles electron defects in the partially-covalent SiO