A bound state consisting of a conduction electron and two valence holes is studied theoretically as a relevant final state in resonant photoemission of ionic crystals. The model includes the on-site repulsion between two holes and the attractive interaction between an electron and a hole on nearest-neighbor sites in a one-dimensional lattice. It is shown that the three-body bound state, called a trion, is stable against dissociation into a free exciton and a hole. The binding energy and the wave function are obtained rigorously by means of scattering theory. For the case of LiF the probability of the Auger transition annihilating the Li 1s hole and creating two 2p holes on different F sites is studied. With the use of the Hartree-Fock-Slater orbitals for Li and F atoms the probability is found to be comparable to that of creating two holes on the same F site. As a result it is proposed that a satellite structure due to formation of the trion bound state is likely to be observed in resonant photoemission spectra of ionic crystals.
ASJC Scopus subject areas
- Condensed Matter Physics