The Transition Between Real and Complex Superconducting Order Parameter Phases in UPt3

Order parameter symmetry is one of the basic characteristics of a superconductor. The heavy fermion compound UPt3 provides a rich system for studying the competition between superconductivity and other forms of electronic order and exhibits two distinct superconducting phases that are characterized...

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Bibliographic Details
Published in:Science (American Association for the Advancement of Science) 2010-06, Vol.328 (5984), p.1368-1369
Main Authors: STRAND, J. D, BAHR, D. J, VAN HARLINGEN, D. J, DAVIS, J. P, GANNON, W. J, HALPERIN, W. P
Format: Article
Language:English
Subjects:
Competition
Condensed matter: electronic structure, electrical, magnetic, and optical properties
Critical currents
Electronics
Exact sciences and technology
Fermions
Heavy-fermion superconductors
Order parameters
Phase transitions
Phases
Physics
Properties of type I and type II superconductors
Proximity effects, weak links, tunneling phenomena, and josephson effects, adreev effect, sn and sns junctions
Superconducting materials (excluding high-tc compounds)
Superconductivity
Superconductors
Symmetry
Tunnel junctions
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Summary:Order parameter symmetry is one of the basic characteristics of a superconductor. The heavy fermion compound UPt3 provides a rich system for studying the competition between superconductivity and other forms of electronic order and exhibits two distinct superconducting phases that are characterized by different symmetries. We fabricated a series of Josephson tunnel junctions on the as-grown surfaces of UPt3 single crystals spanning the a-b plane. By measuring their critical current, we mapped out the magnitude of the superconducting order parameter as a function of the momentum-space direction and temperature. In the high-temperature phase, we observed a sharp node in the superconducting gap at 45 degrees with respect to the a axis; an out-of-phase component appeared in the low-temperature phase, creating a complex order parameter.
ISSN:0036-8075
1095-9203
DOI:10.1126/science.1187943