Dispersive energy transport in disordered solids: Relation to spin-glass relaxation

Abstract
Triplet excitation energy transport on the substitutionally disordered lattice of p-dichlorobenzene in p-dibromobenzene follows a Kohlrausch-type relaxation. Temperature variation reveals β=(1/3 at low temperatures. We describe this behavior either by random-walk processes affected by geometric, energetic, and temporal disorder or by relaxation models suggested by Campbell et al. for spin glasses. We extend the relationship between these two concepts to excitation energy transport in diverse disordered solids.