EFFECTIVE LI-LI INTERACTIONS IN K1-XLIXTAO3

The interaction energy of two Li impurities in a KTaO3 host lattice is calculated within a non-linear polarizable shell model as a function of Li-Li distance, dipole orientation, and bond direction. Our results show a complex dependence of die interaction on these parameters, sug gesting that a large amount of information is lost when representing K 1-xLixTaO3 by means of simplified spin-glass-like models. At low impur ity concentrations, where two-body interactions are dominant, it is ob served that the tendency towards ferroelectric and ferroelastic orderi ng, increases with Li concentration. However, the complexity of the in teractions together with the random spatial distribution of the impuri ties leads to a disordered-frustrated-ground state.