title: Evidence for a multiple superconducting gap in MgB(2) from high-resolution photoemission spectroscopy.
abstract: We study the new binary intermetallic superconductor MgB(2) using high-resolution photoemission spectroscopy. The superconducting-state spectrum measured at 5.4 K shows a coherent peak with a shoulder structure, in sharp contrast to that expected from a simple isotropic-gap opening. The spectrum can be well reproduced using the weighted sum of two Dynes functions with the gap sizes of 1.7 and 5.6 meV. Temperature-dependent study shows that both gaps close at the bulk transition temperature. These results provide spectroscopic evidence for a multiple gap of MgB(2).
authors.affiliation: Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Tsuda
authors.forename: T
authors.initials: T
authors.lastname: Yokoya
authors.forename: T
authors.initials: T
authors.lastname: Kiss
authors.forename: Y
authors.initials: Y
authors.lastname: Takano
authors.forename: K
authors.initials: K
authors.lastname: Togano
authors.forename: H
authors.initials: H
authors.lastname: Kito
authors.forename: H
authors.initials: H
authors.lastname: Ihara
authors.forename: S
authors.initials: S
authors.lastname: Shin