Spectroscopy measurements of superconductor-graphene-normal metal junctions
ORAL
Abstract
We discuss results on single layer graphene junctions made by a graphene sheet in contact with a superconducting tunnel probe and a normal ohmic contact. The superconducting gap of the tunnel probes is well formed at 250 mK. However, we observe an additional conductance gap at smaller biases (a ``subgap'' feature), which is symmetric in bias voltage and oscillates as function of the applied backgate voltage. Even though no supercurrent flow is observed, due to the large spacing of the leads, the observed effects may be due to Andreev bound states. We discuss the possible role of Andreev bound states in determining the inner subgap features of the conductance, and potential spectroscopic signatures arising from the ballistic transport of normal electrons in graphene that travel between the superconducting and the normal contacts.
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Authors
Travis Dirks
University of Illinois at Urbana-Champaign
Yung-Fu Chen
Department of Physics, University of Wisconsin-Madison
University of Wisconsin-Madison
Cesar Chialvo
University of Illinois at Urbana-Champaign
Department of Physics and Materials Research Laboratory, University of Illinois at Urbana-Champaign
B. Uchoa
University of Illinois at Urbana-Champaign
University of Illinois
Taylor Hughes
University of Illinois at Urbana-Champaign
Siddhartha Lal
University of Illinois at Urbana-Champaign
University of Illinois
Dept. of Physics, University of Illinois
Paul Goldbart
University of Illinois at Urbana-Champaign
Universiy of Illinois
University of Illinois
UIUC
Department of Physics and Institute for Condensed Matter Theory, University of Illinois at Urbana-Champaign
Nadya Mason
University of Illinois at Urbana-Champaign
Department of Physics and Materials Research Laboratory, University of Illinois at Urbana-Champaign
