"Reaffirming the dx2-y2 Superconducting Gap Using the Autocorrelation Angle-Resolved Photoemission Spectroscopy of Bi1.5Pb0.55Sr1.6La0.4CuO6+δ"

M. Hashimoto: R.-H. He, J. P. Testaud, W. Meevasana, R. G. Moore, D. H. Lu, Y. Yoshida, H. Eisaki, T. P. Devereaux, Z. Hussain, and Z.-X. Shen ; Phys. Rev. Lett., 04/22/11.

Additional Authors: R.-H. He, J. P. Testaud, W. Meevasana, R. G. Moore, D. H. Lu, Y. Yoshida, H. Eisaki, T. P. Devereaux, Z. Hussain, and Z.-X. Shen

Abstract:

Knowledge of the gap function is important to understand the pairing mechanism for high-temperature (Tc) superconductivity. However, Fourier transform scanning tunneling spectroscopy (FT STS) and angle-resolved photoemission spectroscopy (ARPES) in the cuprates have reported contradictory gap functions, with FT-STS results deviating strongly from a canonical dx2-y2 form. By applying an “octet model” analysis to autocorrelation ARPES, we reveal that a contradiction occurs because the octet model does not consider the effects of matrix elements and the pseudogap. This reaffirms the canonical dx2-y2 superconducting gap around the node, which can be directly determined from ARPES. Further, our study suggests that the FT-STS reported fluctuating superconductivity around the node at far above Tc is not necessary to explain the existence of the quasiparticle interference at low energy.