Theory of Excitons in Phonon Fields

摘要: In Chaps. 1 and 2, we have mainly considered an exciton or excitonic molecule (EM) as elementary electronic excitation in the static spatially periodic field of a rigid crystal, but real crystal lattice is deformable vibrating. The vibrations cause temporally fluctuating potential for exciton. spatial fluctuation gives rise to scattering momentary localization exciton, reflected broadening low-energy tail, respectively, absorption spectra. temporal responsible fine structure (phonon sidebands) deformability causes reverse action: induces distortion around itself, namely, always dressed with phonons. This has effect stabilizing — some cases, even immobilizing energy shift luminescence Not only translational, also relative motion electron hole subject self-induced phonons; particular, optical phonons give dynamical screening electron-hole (e-h) Coulomb attraction, thus reducing effective binding significantly.