Theory of Superconductivity in Mesoscopic Systems

ORAL

Abstract

By using Bogoliubov-de Gennes (BdG) equations, we study superconducting (SC) states in a quasi 2-dimensional system of radius $R$. It is shown that no vortices exist in $s$-wave SC samples with $R < R_c\sim\xi(0)$, the $T=0$ coherence length. We predict that chiral $p$-wave states exhibit superconductivity for $R < R_c$ only in the presence of a vortex with opposite chirality. This {\it reentrant} SC phase is a consequence of non-zero chirality of the pairing order parameter and implies the presence of chiral edge currents. Our study may be applied to sharply probing the pairing symmetry of unconventional superconductors.

*This work is partially supported by Hong Kong RGC Grant GRF HKU707211, HKUST3/CRF/09 and start-up funds at Stanford University (S.R.).

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Authors

  • Jiawei Huo

    • Department of Physics, The University of Hong Kong, Hong Kong, China

  • Weiqiang Chen

    • Department of Physics, The University of Hong Kong, Hong Kong, China

  • Srinivas Raghu

    • Stanford University
    • Department of Physics, Stanford University, Stanford, CA, 94305

  • Fu-Chun Zhang

    • Department of Physics, The University of Hong Kong, Hong Kong, China
    • University of Hong Kong