Tunneling spectra of submicron Bi2Sr2CaCu2O8+δ intrinsic Josephson junctions: evolution from superconducting gap to pseudogap

摘要

Tunneling spectra of near optimally doped, submicron Bi2Sr2CaCu2O8+δ intrinsic Josephsonjunctions are presented, and examined in the region where the superconducting gap evolves into pseudogap.The spectra are analyzed using a self-energy model, proposed by Norman et al., in which both quasiparticlescattering rate Г and pair decay rate ГΔ are considered. The density of states derived from the model hasthe familiar Dynes' form with a simple replacement of Г by γ+ = (Г+ГΔ)/2. The γ+ parameter obtainedfrom fitting the experimental spectra shows a roughly linear temperature dependence, which puts a strongconstraint on the relation between Г and ГΔ We discuss and compare the Fermi arc behavior in thepseudogap phase from the tunneling and angle-resolved photoemission spectroscopy experiments. Ourresults indicate an excellent agreement between the two experiments, which is in favor of the precursorpairing view of the pseudogap.