Berlin 2012 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
TT: Fachverband Tiefe Temperaturen
TT 3: Correlated Electrons: Heavy Fermions
TT 3.3: Vortrag
Montag, 26. März 2012, 10:00–10:15, H 3005
Resonant magnetic exciton mode in the heavy-fermion antiferromagnet CeB6 — G. Friemel1, Y. Li1, A. V. Dukhnenko2, N. Y. Shitsevalova2, N. E. Sluchanko3, A. Ivanov4, V. B. Filipov2, B. Keimer1, and •D. S. Inosov1 — 1MPI für Festkörperforschung, Stuttgart, Germany. — 2Institute for Problems of Material Sciences, Kiev, Ukraine. — 3General Physics Institute, Moscow, Russia. — 4Institut Laue-Langevin, Grenoble, France.
Resonant magnetic excitations are widely recognized as hallmarks of unconventional superconductivity in copper oxides, iron pnictides, and heavy-fermion compounds. Model calculations have related these modes to the microscopic properties of the pair wave function, but the mechanisms of their formation are still debated. Here we report the discovery of a similar resonant mode in the non-superconducting antiferromagnetic heavy-fermion metal CeB6. Unlike conventional magnons, the mode is non-dispersive and is sharply peaked around a wave vector separate from those characterizing the antiferromagnetic order. The magnetic intensity distribution rather suggests that the mode is associated with a coexisting antiferro-quadrupolar order parameter, which has long remained “hidden” to the neutron-scattering probes. The mode energy increases continuously below the onset temperature for antiferromagnetism, in parallel to the opening of a nearly isotropic spin gap throughout the Brillouin zone. These attributes bear strong similarity to those of the resonant modes in unconventional superconductors, indicating the dominance of itinerant spin dynamics in the ordered low-temperature phases of CeB6.