Superconducting gap and order parameter in
- 1 July 1994
- journal article
- research article
- Published by American Physical Society (APS) in Physical Review B
- Vol. 50 (1) , 590-593
- https://doi.org/10.1103/physrevb.50.590
Abstract
Using angle-resolved photoemission, we observed a nonzero superconducting gap and the presence of a superconducting condensate along all three major symmetry directions. We find that the gap is highly anisotropic, with a gap as small as 1–2 meV along Γ-Y, 4–8 meV along Γ-X, and 14–20 meV along Γ-M. We argue that our data imply either an anisotropic s-wave order parameter or an unconventional, two-component order parameter, and that measuring the size of the gap does not by itself distinguish between the two possibilities. We propose a phenomenological unconventional order parameter, and note the quantitative agreement between theory and experiment.Keywords
This publication has 33 references indexed in Scilit:
- Symmetry of the superconducting order parameter inPhysical Review Letters, 1993
- Anomalously large gap anisotropy in the a-b plane ofPhysical Review Letters, 1993
- Evidence for k-dependent, in-plane anisotropy of the superconducting gap inPhysical Review B, 1992
- Nature of the high-binding-energy dip in the low-temperature photoemission spectra ofPhysical Review B, 1992
- Electronic spectrum of the high-temperature superconducting statePhysical Review Letters, 1991
- High-resolution angle-resolved photoemission study of the Fermi surface and the normal-state electronic structure ofPhysical Review B, 1990
- Superconducting Gap in Bi-Sr-Ca-Cu-O by High-Resolution Angle-Resolved Photoelectron SpectroscopyScience, 1989
- On the Superconducting Energy Gap in Bi 2 Sr 2 CaCu 2 O 8 Investigated by High-Resolution Angle-Resolved PhotoemissionEurophysics Letters, 1989
- High-Resolution Photoemission Study of the Low-Energy Excitations Reflecting the Superconducting State of Bi-Sr-Ca-Cu-O Single CrystalsPhysical Review Letters, 1989
- Evidence from angle-resolved resonant photoemission for oxygen-2p nature of the Fermi-liquid states in Bi2CaSr2Cu2O8Nature, 1988