title: Determination of gap symmetry from angle-dependent H(c2) measurements on CeCu₂Si₂.
abstract: The tetragonal heavy-fermion compound CeCu₂Si₂ exhibits a superconducting ground state (S type, T(c) = 0.67 K) close to a magnetic instability. Here, we present angle-resolved resistivity measurements of the upper critical field H(c2). In-plane rotation of S-type CeCu₂Si₂ single crystals reveals a fourfold oscillation of H(c2). An extended weak-coupling BCS model for a d-wave symmetry including strong Pauli-limiting effects confirms the aforementioned angular dependence and points towards d(xy) symmetry of the order parameter.
authors.affiliation: Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany. Hugo.Vieyra@cpfs.mpg.de
authors.forename: H A
authors.initials: HA
authors.lastname: Vieyra
authors.forename: N
authors.initials: N
authors.lastname: Oeschler
authors.forename: S
authors.initials: S
authors.lastname: Seiro
authors.forename: H S
authors.initials: HS
authors.lastname: Jeevan
authors.forename: C
authors.initials: C
authors.lastname: Geibel
authors.forename: D
authors.initials: D
authors.lastname: Parker
authors.forename: F
authors.initials: F
authors.lastname: Steglich