PRINCIPLE OF LOCAL ENERGY MINIMUM FOR DONOR-ACCEPTOR SYSTEMS WITH LOWCOMPENSATION

The charged states and structures of one-acceptor local complexes (OLC ) are studied as functions of external potentials for donor-acceptor s ystems with low compensations K. The criterion of a two-acceptor local complex (TLC) is formulated. It is used to derive stochastic equation s for self-consistent fluctuating potentials (FP) in the OLC ensemble and to find an expression for the Fermi level mu(K) of impurity electr ons via the on-site distribution of FP. It is shown in the ''smeared s ite'' approximation that the asymptotic behavior of mu(K) for small K is determined by the average size of the TLC and by self-consistent sc reening effects in the OLC ensemble.