Direct evidence for self-trapping of excitons by indium nanowires at In/Si(111) surface

摘要

We report on the real-space observation of self-trapped excitons using scanning tunneling microscope. Electrons of In nanowires transfer to the Si substrate, yielding charge-transfer excitons at In/Si interface. The strong coupling between excitons and lattice vibrations leads to the exciton localization at low carrier density and 80.0 K. Exciton condensation was observed at the proper carrier density and its microscopic origin is discussed.