Strong-coupling d-wave superconductivity in PuCoGa5 probed by point-contact spectroscopy
We report on point-contact spectroscopy measurements in PuCoGa5, a moderate heavy-fermion superconductor with a record high critical temperature Tc = 18.5 K. The results prove that the wavefunction of the paired electrons has a d-wave symmetry, with four lobes and nodes, and show that the pairing is likely to be mediated by spin fluctuations. Electronic structure calculations, which take into account the full structure of the f-orbital multiplets of Pu, provide a hint of the possible origin of these fluctuations.
D. Daghero, M. Tortello, G. A. Ummarino, J.-C. Griveau, E. Colineau, R. Eloirdi, A. B. Shick, J. Kolorenč, A.I. Lichtenstein, and R. Caciuffo, Nat. Commun. 3 (2012) 786
