Zeeman-limited Superconductivity in Crystalline Al Films

ORAL

Abstract

We report the evolution of the Zeeman-limited superconducting phase diagram (PD) in ultra-thin crystalline Al films. Parallel critical field measurements, down to 50 mK, were made across the superconducting tricritical point of epitaxially-grown Al films ranging in thickness from 7 monolayers (ML) to 30 ML. The resulting phase boundaries were compared with the quasi-classical theory of a Zeeman-mediated transition between a homogeneous BCS condensate and a spin polarized Fermi liquid. Films thicker than $\sim~20$ ML showed good agreement with theory, but thinner films exhibited an anomalous PD that cannot be reconciled within a homogeneous BCS framework.

*DE-FG02-07ER46420, ONR-N00014-14-1-0330, NSF- DMR-1506678, CIG-618258

–

Authors

  • Philip Adams

    • Louisiana State University
    • Louisiana State Univ - Baton Rouge

  • Hyoundo Nam

    • The University of Texas

  • Chih-Kang Shih

    • The University of Texas
    • The University of Texas at Austin
    • Department of Physics, The University of Texas at Austin, TX 78712
    • Univ of Texas, Austin
    • University of Texas at Austin

  • Gianluigi Catelani

    • Peter Gr\"unberg Institut (PGI-2), Forschungszentrum J\"ulich
    • Forschungszentrum J\"ulich
    • Peter Grunberg Institut (PGI-2) and JARA Institute for Quantum Information, Forschungszentrum Julich, 52425 Julich, Germany
    • Forschungszentrum Jülich, Peter Grünberg Institut (PGI-2), 52425 Jülich, Germany