Strong self-trapping in semiconducting two-band systems.

Abstract

Strong electron self-trapping is investigated at an energy gain exceeding (or close to) an interband gap width. Interactions between states in self-trapping and ``nonparent'' bands are taken into account. These interactions lead to changes in the occupation of the state in question: singly occupied or unoccupied states become doubly occupied. The shape of the adiabatic potentials is investigated for different initial occupation of the self-trapping state. A standard single-well potential can be to be transformed to a double-well potential. The extra minimum describes a strongly hybridized practically doubly occupied self-trapped state. The single-particle self-trapping energy and pair-correlation energy appear to depend strongly on these effects. The value of the pair self-trapping correlation energy is shown to be limited to about half of the gap width.