title: Photoemission studies of high-tc superconductors: the superconducting gap.
abstract: Over the last several years there have been great improvements in the energy resolution and detection efficiency of angle-resolved photoemission spectroscopy. These improvements have made it possible to discover a number of fascinating features in the electronic structure of the high transition temperature (T(c)) superconductors: apparently bandlike Fermi surfaces, flat-band saddle points, and nested Fermi surface sections. Recent work suggests that these features, previously thought explainable only by one-electron band theory, may be better understood with a many-body approach. Furthermore, other properties of the high-T(c) superconductors, which are difficult to understand with band theory, are well described using a many-body picture. Angle-resolved photoemission spectroscopy has also been used to investigate the nature of the superconducting pairing state, revealing an anisotropic gap consistent with a d-wave order parameter and fueling the current debate over s-wave versus d-wave superconductivity.
authors.forename: Z X
authors.initials: ZX
authors.lastname: Shen
authors.forename: W E
authors.initials: WE
authors.lastname: Spicer
authors.forename: D M
authors.initials: DM
authors.lastname: King
authors.forename: D S
authors.initials: DS
authors.lastname: Dessau
authors.forename: B O
authors.initials: BO
authors.lastname: Wells