ELECTRONIC PAIRING MECHANISM DUE TO BAND MODIFICATION IN A 2-BAND MODEL - T-C EVALUATION

Following the electronic model developed by us previously (Mizia and R omanowski, Mizia) we estimate the superconducting transition temperatu re in a simple electronic two-band model for materials characterized b y a broad superconducting band and a narrow level within the same ener gy range. A large electron deformation coupling constant and large ele ctron correlation effects are assumed. It is shown that high-temperatu re superconductivity is entirely possible within a range of reasonable electronic parameters. This model does not assume any artificial inte ractions to obtain a negative pairing potential. Instead, the negative part of the electronic interaction potential comes from the modificat ion of the electron dispersion relation with growing number of superco nducting pairs. Such a modification is possible in soft electronic sys tems, i.e. in systems partial to band modification due to large intern al stresses, strong electronic correlation effects and broad band narr ow level charge transfer during the superconducting transition.