Non-conventional superconductivity in the strong-coupling limit for the heavy fermion system CeCoIn$_{5}$

Y. FASANO; P. SZABO; P. PEDRAZZINI; J. KACMARCIK; Z. PRIBULOVA; P. SAMUELY; V. CORREA

Bariloche

Encuentro; Poster presentation en el XIV Encuentro de Superficies y materiales nanoestructurados NANO2014; 2014

Centro Atómico Bariloche

Heavy-fermion systems such as   CeCoIn$_{5}$ are interestingcandidates to study the microscopic coupling giving rise tounconventional superconductivity in concomitance with magneticorder. Scanning tunnelling microscopy is a suitable technique tostudy this issue since measuring the tunnel conductance providesinformation on the local density of states of the system. Wepresent data on the temperature-evolution of the quasiparticleexcitation spectrum of CeCoIn$_{5}$ between 300,mK and 3,K($T_{ m c} = 2.2$,K). For temperatures  $T< T_{ m c}$ thespectral weight can be reasonably fitted considering a d-wavesymmetry for the superconducting gap . The obtained ratio $2Delta/ k T_{ m c} sim 6$ indicates CeCoIn$_{5}$ is anon-conventional superconductor in the strong limit, finding alsosupported by specific heat measurements. In striking parallel withcuprate superconductors, the tunnelling conductance shows adepletion at energies smaller than  $Delta$ for temperatureslarger than $T_{ m c}$, suggesting the existence of a pseudogapphase up to $1.25 T_{ m c}$.