title: Molecular pairing and fully gapped superconductivity in Yb-doped CeCoIn(5).
abstract: The recent observation of fully gapped superconductivity in Yb doped CeCoIn_{5} poses a paradox, for the disappearance of nodes suggests that they are accidental, yet d-wave symmetry with protected nodes is well established by experiment. Here, we show that composite pairing provides a natural resolution: in this scenario, Yb doping drives a Lifshitz transition of the nodal Fermi surface, forming a fully gapped d-wave molecular superfluid of composite pairs. The T^{4} dependence of the penetration depth associated with the sound mode of this condensate is in accordance with observation.
authors: Center for Materials Theory, Rutgers University, Piscataway, New Jersey 08854, USA.
authors: Onur
authors: O
authors: Erten
authors: Department of Physics and Astronomy, Iowa State University, 12 Physics Hall, Ames, Iowa 50011, USA.
authors: Rebecca
authors: R
authors: Flint
authors: Center for Materials Theory, Rutgers University, Piscataway, New Jersey 08854, USA and Department of Physics, Royal Holloway, University of London, Egham, Surrey TW20 0EX, United Kingdom.
authors: Piers
authors: P
authors: Coleman