title: Evidence for Eight-Node Mixed-Symmetry Superconductivity in a Correlated Organic Metal.
abstract: We report on a combined theoretical and experimental investigation of the superconducting state in the quasi-two-dimensional organic superconductor κ-(ET)_{2}Cu[N(CN)_{2}]Br. Applying spin-fluctuation theory to a low-energy, material-specific Hamiltonian derived from ab initio density functional theory we calculate the quasiparticle density of states in the superconducting state. We find a distinct three-peak structure that results from a strongly anisotropic mixed-symmetry superconducting gap with eight nodes and twofold rotational symmetry. This theoretical prediction is supported by low-temperature scanning tunneling spectroscopy on in situ cleaved single crystals of κ-(ET)_{2}Cu[N(CN)_{2}]Br with the tunneling direction parallel to the layered structure.
authors.affiliation: Institut für Theoretische Physik, Goethe-Universität Frankfurt, Max-von-Laue-Strasse 1, 60438 Frankfurt am Main, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Guterding
authors.affiliation: Graduate School Materials Science in Mainz, Staudingerweg 9, 55128 Mainz, Germany.|Institut für Physik, Johannes Gutenberg-Universität Mainz, Staudingerweg 7, 55128 Mainz, Germany.
authors.forename: Sandra
authors.initials: S
authors.lastname: Diehl
authors.affiliation: Institut für Theoretische Physik, Goethe-Universität Frankfurt, Max-von-Laue-Strasse 1, 60438 Frankfurt am Main, Germany.
authors.forename: Michaela
authors.initials: M
authors.lastname: Altmeyer
authors.affiliation: Institut für Physik, Johannes Gutenberg-Universität Mainz, Staudingerweg 7, 55128 Mainz, Germany.
authors.forename: Torsten
authors.initials: T
authors.lastname: Methfessel
authors.affiliation: Physikalisches Institut, Goethe-Universität Frankfurt, Max-von-Laue-Strasse 1, 60438 Frankfurt am Main, Germany.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Tutsch
authors.affiliation: Physikalisches Institut, Goethe-Universität Frankfurt, Max-von-Laue-Strasse 1, 60438 Frankfurt am Main, Germany.
authors.forename: Harald
authors.initials: H
authors.lastname: Schubert
authors.affiliation: Physikalisches Institut, Goethe-Universität Frankfurt, Max-von-Laue-Strasse 1, 60438 Frankfurt am Main, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Lang
authors.affiliation: Physikalisches Institut, Goethe-Universität Frankfurt, Max-von-Laue-Strasse 1, 60438 Frankfurt am Main, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Müller
authors.affiliation: Physikalisches Institut, Goethe-Universität Frankfurt, Max-von-Laue-Strasse 1, 60438 Frankfurt am Main, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Huth
authors.affiliation: Institut für Theoretische Physik, Goethe-Universität Frankfurt, Max-von-Laue-Strasse 1, 60438 Frankfurt am Main, Germany.
authors.forename: Harald O
authors.initials: HO
authors.lastname: Jeschke
authors.affiliation: Institut für Theoretische Physik, Goethe-Universität Frankfurt, Max-von-Laue-Strasse 1, 60438 Frankfurt am Main, Germany.
authors.forename: Roser
authors.initials: R
authors.lastname: Valentí
authors.affiliation: Institut für Physik, Johannes Gutenberg-Universität Mainz, Staudingerweg 7, 55128 Mainz, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Jourdan
authors.affiliation: Institut für Physik, Johannes Gutenberg-Universität Mainz, Staudingerweg 7, 55128 Mainz, Germany.
authors.forename: Hans-Joachim
authors.initials: HJ
authors.lastname: Elmers