Effect of the coupling to a superconductor on the level statistics of a metal grain in a magnetic field

Journal Article · Mon Apr 01 04:00:00 EST 1996 · Physical Review Letters

DOI:https://doi.org/10.1103/PhysRevLett.76.2981· OSTI ID:284511

Frahm, K M; Brouwer, P W; Melsen, J A; Beenakker, C W ^[1]

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1. Instituut-Lorentz, University of Leiden, P.O. Box 9506, 2300 RA Leiden (The Netherlands)

A theory is presented for the statistics of the excitation spectrum of a disordered metal grain in contact with a superconductor. A magnetic field is applied to fully break time-reversal symmetry in the grain. Still, an excitation gap of the order of {delta} opens up provided {ital N}{Gamma}{sup 2}{approx_gt}1. Here {delta} is the mean level spacing in the grain, {Gamma} the tunnel probability through the contact with the superconductor, and {ital N} the number of transverse modes in the contact region. This provides a microscopic justification for the new random-matrix ensemble of Altland and Zirnbauer. {copyright} {ital 1996 The American Physical Society.}

• OSTI ID: 284511
• Journal Information: Physical Review Letters, Journal Name: Physical Review Letters Journal Issue: 16 Vol. 76; ISSN 0031-9007; ISSN PRLTAO
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
ENERGY GAP
EXCITATION
GRAIN BOUNDARIES
MAGNETIC FIELDS
METALS
PROXIMITY EFFECT
RANDOMNESS
SUPERCONDUCTIVITY
SYMMETRY BREAKING