Point-contact spectroscopy in heavy-fermion superconductors

Mikael Fogelström, W. K. Park, L. H. Greene, G. Goll, Matthias J. Graf

Research output: Contribution to journalArticle

Abstract

We develop a microscopic model to calculate point-contact spectra between a metallic tip and a superconducting heavy-fermion system. We apply our tunneling model to the heavy fermion CeCoIn5, both in the normal and superconducting states. In point contact and scanning tunneling spectroscopy many heavy-fermion materials, such as CeCoIn5, exhibit an asymmetric differential conductance, dI/dV, combined with a strongly suppressed Andreev reflection signal in the superconducting state. We argue that both features may be explained in terms of a multichannel tunneling model in the presence of localized states near the interface. We find that it is not sufficient to tunnel into two itinerant bands of light and heavy electrons to explain the Fano line shape of the differential conductance. Localized states in the bulk or near the interface are an essential component for quantum interference to occur when an electron tunnels from the metallic tip of the point contact into the heavy-fermion system.

Original languageEnglish (US)
Article number014527
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume82
Issue number1
DOIs
StatePublished - Jul 20 2010

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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