Dresden 2006 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
TT: Tiefe Temperaturen
TT 8: Correlated Electrons: Heavy Fermions
TT 8.9: Vortrag
Montag, 27. März 2006, 16:45–17:00, HSZ 301
Probing the Electronic Properties of the Heavy-Fermion Superconductor CeCoIn5 — •G. Goll1, T. Brugger1, M. Marz1, T. Sayles2, and M. B. Maple2 — 1Phys. Inst., Universität Karlsruhe, 76128 Karlsruhe, Germany — 2Inst. for Pure and Applied Phys. Sciences, University of California, San Diego, La Jolla, CA 92093, USA
In many U- and Ce-based heavy-fermion superconductors, as well as in the oxide superconductors, the superconducting (sc) properties differ from those of a classical superconductor due to the presence of strong electron-electron correlations [1]. A recent example is CeCoIn5, a heavy-fermion superconductor with Tc=2.3 K, where among other exotic properties a power-law behavior of the thermodynamic and transport properties in the sc state gives evidence that the order parameter (op) has line nodes and probably dx2−y2 symmetry. Several groups performed point-contact (pc) experiments on CeCoIn5 in order to elucidate the gap structure. However, there is still some controversy on the interpretation of the structures in the differential conductance dI/dV vs. V which has mainly to do with the determination of the regime of current flow through the pc. We report on measurements of dI/dV vs. V on Pt-CeCoIn5 pc’s in the normal and sc states down to 30mK in zero and applied magnetic fields and we discuss the pc regime in detail. In the normal state the spectra exhibit a pronounced asymmetry which is not affected by an applied field up to B=6 T. The spectra in the sc state support a d-wave op scenario for CeCoIn5, in line with the pc data obtained by other groups.
[1] G. Goll: Unconventional Superconductors, STMP, Vol. 214, Springer-Verlag 2005.