Abstract
We have performed ultrahigh-resolution angle-resolved photoemission spectroscopy to directly study the large superconducting (SC) gap anisotropy of . We succeed in measuring momentum dependence of SC gap for individual Fermi surface (FS) sheets, which demonstrates complexity of SC gap in a phonon-mediated superconductor. Within measured regions on FS sheets, we find a pointlike minimum of SC gap, whose positions can be connected by the known nesting vector. This shows close correlation between the nesting vector and node formation.
- Received 12 March 2010
DOI:https://doi.org/10.1103/PhysRevB.81.180509
©2010 American Physical Society