We report the detuning dependence of the excitonic optical Stark shift in the inorganic-organic layered semiconductor (C6H5C 2H4NH3)2PbI4 as a typical material in which the effective Coulomb interaction is strong. We show the polarization dependence of the detuning spectra, i.e., the shifts as functions of continuously changing pump photon energy, over the range of 350 meV below the exciton resonance. It is found that in the opposite-circularly and colinearly polarized configurations for pump and probe lights, the shift changes its sign at 50 meV below the exciton resonance and is resonantly enhanced around it. With larger detuning, in any polarizations, blue shifts are much smaller than predicted by the dressed exciton model. We present a tentative model, which is an extended dressed exciton model including the excitonic molecule and unbound biexcitons phenomenologically. The model reproduces the experimental result quite well.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 2004 Apr 1|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics