Site correlation effects in the dynamics of iron impurities Fe~(2+)/Fe~(3+) and antisite defects Nb_(Li)~(4+)/Nb_(Li)~(5+) after a short-pulse excitation in LiNbO_3

摘要

The correlation effects between excitation and trapping sites after light excitation in a Li-deficient Fe-doped LiNbO_3 crystal have been quantitatively analyzed. They appear as a direct consequence of the thermally activated random transport (hopping) of electrons (free polarons) by using a Monte Carlo approach. The physical consequences of those effects, not present in usual coherent band-transport analyses, are explored and discussed in the light of available experiment. In particular, nonexponential decay kinetics for the evolution of electrons trapped at antisites (small polarons) are predicted.