2013/07/16 by Guo‐meng Zhao, Zhao, Guo-meng
Chemistry · Engineering · Physics and Astronomy · #FOS: Physical sciences #Inorganic Fluorides and Related Compounds #Physics of Superconductivity and Magnetism #Superconducting Materials and Applications #Superconductivity (cond-mat.supr-con)
paper · pdf · doi:10.48550/arxiv.1307.4175
openalex publication_date 2013/07/16 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We have calculated the tunneling conductance of a superconductor-insulator-superconductor junction based on the polaron-bipolaron theory of superconductivity. The predicted incoherent hump features are in quantitative agreement with tunneling spectra of optimally doped Bi2Sr2CaCu2O8+y and Bi2Sr2Ca2Cu3O10+y. We further show that angle-resolved photoemission spectra of underdoped cuprates are consistent with the Bose-Einstein condensation of inter-site bipolarons and that the superconducting gap symmetry is d-wave, which is determined by the anomalous kinetic process rather than by the pairing interaction. In the overdoped cuprates (BCS-like superconductors), the superconducting gap symmetry is the same as the pairing symmetry, which is found to be extended s-wave with eight line nodes in hole-doped cuprates and nodeless s-wave in electron-doped cuprates. The polaronic effect significantly enhances the density of states at the Fermi level and the effective electron-phonon coupling constant for low-energy phonon modes, which is the key to the understanding of high-temperature superconductivity.