Berlin 2008 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 6: Correlated Electrons: Heavy Fermions
TT 6.5: Vortrag
Montag, 25. Februar 2008, 10:30–10:45, EB 202
A precursor state to unconventional superconductivity in the heavy fermion superconductor CeIrIn5 — •Sunil Nair1, S. Wirth1, M. Nicklas1, J. L. Sarrao2, J. D. Thompson2, Z. Fisk3, and F. Steglich1 — 1Max Planck Institute for Chemical Physics of Solids, Noethnitzer Str. 40, Dresden 01187, Germany. — 2Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA. — 3University of California, Irvine, California 92697, USA.
The CeMIn5 (where M: Co, Rh or Ir) family of heavy fermion systems is currently in vogue; not only for the host of novel properties they exhibit in its normal and superconducting states, but also for the rather striking resemblance many of these properties have with the cuprate high temperature superconductors. Here, we present sensitive measurements of the Hall effect and magnetoresistance in CeIrIn5, in the temperature range 0.05 K ≤ T ≤ 2.5 K and magnetic fields up to 15 T. The magnetoresistance is used to demarcate the presence of a low temperature Kondo coherent state. Furthermore, by means of Kohler’s scaling plots, the crossover from a Landau-Fermi liquid to a non-Fermi liquid regime is inferred. The functional form of the Hall resistivity is observed to be in concurrence with that expected for a compensated metal. The most striking observation pertains to the presence of a precursor state to superconductivity characterized by a change in the Hall scattering rate, in similarity to the pseudogap state in the cuprates. Moreover, the critical fields of the precursor state and the superconducting one can be scaled on to each other, implying that they could arise from the same underlying physical mechanism.