Evidence of Strong Electron Phonon Interaction in Iron Doped Bi2Sr2Ca1Cu2O8+d

NESTOR E. MASSA; PABLO ETCHEGOIN; CARLOS FAINSTEIN

Rio de Janeiro

Congreso; Proceedings of the ICTPS '90 International Conference; 1990

ICTP

We have already shown that infrared laser photoinduced spectra of Bi based ceramic superconductor (n=2 phase) doped with iron show a highly polarizable environment at about 700 cm-1 close to the longitudinal optical mode frequency that we characterize as due to trapped polarons. This modifies the higher frequency side of the Cu-O phonon feature at 630 cm-1 which is currently associated with a stretching mode in the plane. In this communication we report that by increasing the Fe doping up to 25% we succeeded in unveiling the electron-phonon interaction related to that stretching mode. Infrared transmission and reflection spectra show an unusual dip at the longitudinal optical frequency . This feature may be understood as due to the coupling of carriers with the field that would rise the transverse-longitudinal optical splitting in purely ionic materials. WE hypothesize that this should lead to a Raman active longitudinal phonon due to the Frölich interaction