Rapid change of superconductivity and electron-phonon coupling through critical doping in Bi-2212

In this study, we used angle-resolved photoemission spectroscopy to find a pronounced correlation between the superconducting gap and the bosonic coupling strength near the Brillouin zone boundary in Bi2Sr2CaCu2O8+. The bosonic coupling strength rapidly increases from the overdoped Fermi liquid regime to the optimally doped strange metal, concomitant with the quadrupled superconducting gap and the doubled gap-to-Tc ratio across the pseudogap boundary. This synchronized lattice and electronic response suggests that the effects of electronic interaction and the electron-phonon coupling (EPC) reinforce each other in a positive-feedback loop upon entering the strange-metal regime, which in turn drives a stronger superconductivity.

Source: ScienceNOW - October 4, 2018 Category: Science Authors: He, Y., Hashimoto, M., Song, D., Chen, S.- D., He, J., Vishik, I. M., Moritz, B., Lee, D.- H., Nagaosa, N., Zaanen, J., Devereaux, T. P., Yoshida, Y., Eisaki, H., Lu, D. H., Shen, Z.- X. Tags: Physics reports Source Type: news