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arXiv · 1708.01900

Local nodal Cooper pairs in multiorbital systems

Kazumasa Hattori·Takuya Nomoto·Takashi Hotta·Hiroaki Ikeda
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Abstract

We show the emergence of a new class of superconductivity in multiorbital systems, focusing on non-Kramers f$^2$ states. The Cooper pairs in this class of superconductivity mainly consist of local pairs with the same symmetry as the local f$^2$ ground states. When the local ground state is an anisotropic representation, the superconducting gap has nodes on the Fermi surface. This nodal superconductivity is mediated by the strong onsite inter-orbital attractions as a consequence of negative-$U$ physics generalized to multiorbital systems. We show that this is indeed realized in a simple two-orbital model with antiferro Hund's coupling and enhanced inter-orbital interaction derived via a systematic local down folding. Finally, we briefly discuss superconductivity in Pr-1-2-20 compounds, UBe$_{13}$, and PrOs$_4$Sb$_{12}$ in view of the present mechanism.

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Kazumasa Hattori, Takuya Nomoto, Takashi Hotta, Hiroaki Ikeda. 2017-08-06. Local nodal Cooper pairs in multiorbital systems. https://doi.org/10.7566/jpsj.86.113702

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