Correlation and Collective Modes in Narrow Band Materials.
Final rept. 1 Oct 84-30 Sep 85,
GEORGIA INST OF TECH ATLANTA SCHOOL OF PHYSICS
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Correlation and collective modes have been studied for systems with quite localized valence or conductance bands. In particular this research has been concerned with localized electron-hole states and how they contribute with other excitations to the dynamical response of the system. Important aspects studied have been the effects of exciton or exciton-like states on superconducting properties, electron energy loss spectra and optical spectra. Initially the system studied has been CuCl for which a tight-binding model was used. The results show that strong effects due to localized excitations of d-band electrons greatly affect the dynamical response and the effective electron interaction. Off-diagonal matrix elements of the inverse dielecttric citation spectrum, producing exciton resonances in the band gap. The exciton resonance in the dynamical response is necessary to obtain the appropriate attractive effective electron interaction for superconductivity. Models have also been set up to relate the dynamical response including local field effects to the superconducting transition temperature and gap function. The strong localization effects also will affect the loss spectra and optical spectra. Keywords include Transition metals Copper Correlation Excitons Dielectric response Interband excitation Optical spectra Energy loss spectra and Superconductivity.
- Electricity and Magnetism
- Quantum Theory and Relativity