Strong-coupling d-wave superconductivity in PuCoGa₅ probed by point-contact spectroscopy.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 22510691.
- Also identified by DOI 10.1038/ncomms1785 and PMC identifier 3337991.
- Licence recorded as CC BY-NC-SA.
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Abstract
Superconductivity is due to an attractive interaction between electrons that, below a critical temperature, drives them to form Cooper pairs and to condense into a ground state separated by an energy gap from the unpaired states. In the simplest cases, the pairing is mediated by lattice vibrations and the wavefunction of the pairs is isotropic. Less conventional pairing mechanisms can favour more exotic symmetries of the Cooper pairs. Here, we report on point-contact spectroscopy measurements in PuCoGa(5), a moderate heavy-fermion superconductor with a record high critical temperature T(c)=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.