Optical studies of charge dynamics in optimally doped Bi2Sr2CaCu2O8+δ -: art. no. 144514

Systematic temperature-dependent optical studies of optimally doped Bi2Sr2CaCu2O8+delta (OP Bi2212) single crystals have been carried out. An electron-boson spectral function peaked at 43 meV is derived in the normal state at 100 K, indicating that the most significant spectral feature in OP Bi2212 is a resonance at 43 meV. The optical data below T-c show that this boson is directly involved in the pair formation in OP Bi2212. Origins of the 43 meV mode are discussed.