title: Two-band superconductivity in MgB2.
abstract: The study of the anisotropic superconductor MgB2 using a combination of scanning tunneling microscopy and spectroscopy reveals two distinct energy gaps at Delta(1)=2.3 meV and Delta(2)=7.1 meV at 4.2 K. Different spectral weights of the partial superconducting density of states are a reflection of different tunneling directions in this multiband system. Temperature evolution of the tunneling spectra follows the BCS scenario [Phys. Rev. Lett. 3, 552 (1959)]] with both gaps vanishing at the bulk T(c). The data confirm the importance of Fermi-surface sheet dependent superconductivity in MgB2 proposed in the multigap model by Liu et al. [Phys. Rev. Lett. 87, 087005 (2001)]].
authors.affiliation: Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.
authors.forename: M
authors.initials: M
authors.lastname: Iavarone
authors.forename: G
authors.initials: G
authors.lastname: Karapetrov
authors.forename: A E
authors.initials: AE
authors.lastname: Koshelev
authors.forename: W K
authors.initials: WK
authors.lastname: Kwok
authors.forename: G W
authors.initials: GW
authors.lastname: Crabtree
authors.forename: D G
authors.initials: DG
authors.lastname: Hinks
authors.forename: W N
authors.initials: WN
authors.lastname: Kang
authors.forename: Eun-Mi
authors.initials: EM
authors.lastname: Choi
authors.forename: Hyun Jung
authors.initials: HJ
authors.lastname: Kim
authors.forename: Hyeong-Jin
authors.initials: HJ
authors.lastname: Kim
authors.forename: S I
authors.initials: SI
authors.lastname: Lee