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Gap anisotropy in Bi[sub 2]Sr[sub 2]CaCu[sub 2]O[sub 8+[delta]] by ultrahigh-resolution angle-resolved photoemission

Journal Article · · Physical Review, B: Condensed Matter; (United States)
; ;  [1]; ; ; ;  [2]
  1. Materials Science Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States) Department of Physics, University of Illinois at Chicago, 845 West Taylor Street, Chicago, Illinois 60607 (United States)
  2. Materials Science Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States)

Ultrahigh-resolution ([Delta][ital E] up to 10 meV) angle-resolved photoemission spectroscopy on single crystals of Bi[sub 2]Sr[sub 2]CaCu[sub 2]O[sub 8+[delta]] (Bi-2212) show a highly anisotropic superconducting energy gap: the gap is minimized, with a value close to zero, along the [Gamma]-[ital X] and [Gamma]-[ital Y] symmetry directions, while a large gap ([Delta]=22 meV) is observed along the [Gamma]-[ital [bar M]] (Cu-O bond) direction. However, the observation of gap anisotropy may depend on sample conditions; in a few cases the gap becomes more isotropic. A dip in the spectral weight at 65 meV below the Fermi energy is clearly observed only in samples with an anisotropic gap.

DOE Contract Number:
W-31109-ENG-38
OSTI ID:
7045279
Journal Information:
Physical Review, B: Condensed Matter; (United States), Journal Name: Physical Review, B: Condensed Matter; (United States) Vol. 50:2; ISSN PRBMDO; ISSN 0163-1829
Country of Publication:
United States
Language:
English