Regensburg 2007 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
TT: Fachverband Tiefe Temperaturen
TT 17: Heavy Fermions
TT 17.13: Vortrag
Mittwoch, 28. März 2007, 17:15–17:30, H18
Theory of magnetic excitons in the heavy-fermion superconductor UPd2Al3 — •Jun Chang1, Ilya Eremin1,2, Peter Thalmeier3, and Peter Fulde1 — 1Max-Planck Institut für Physik komplexer Systeme, D-01187 Dresden, Germany — 2Institute für Mathematische und Theoretische Physik, Technische Universität Carolo-Wilhelmina zu Braunschweig, 38106 Braunschweig, Germany — 3Max-Planck Institut für Chemische Physik fester Stoffe, D-01187 Dresden, Germany
We analyze the influence of unconventional superconductivity on the magnetic excitations in the heavy fermion compound UPd2Al3. We show that it leads to the formation of a bound state at energies well below 2Δ0 at the antiferromagnetic wave vector Q=(0,0,π/c). Its signature is a resonance peak in the spectrum of magnetic excitations in good agreement with results from inelastic neutron scattering. Furthermore we investigate the influence of antiferromagnetic order on the formation of the resonance peak. We find that its intensity is enhanced due to intraband transitions induced by the reconstruction of Fermi surface sheets. We determine the dispersion of the resonance peak near Q and show that it is dominated by the magnetic exciton dispersion associated with local moments. We demonstrate by a microscopic calculation that UPd2Al3 is another example in which the unconventional nature of the superconducting order parameter can be probed by means of inelastic neutron scattering (INS) and determined unambiguously.