Vortex dynamics in a NbN film studied by terahertz spectroscopy

Y. Ikebe, R. Shimano, M. Ikeda, T. Fukumura, M. Kawasaki

Research output: Contribution to journalArticle

25 Citations (Scopus)

Abstract

We have investigated the effect of vortex dynamics on high-frequency conductivity of a superconducting NbN film by using terahertz time-domain spectroscopy. The complex conductivity of the mixed state up to 7 T is determined without using Kramers-Kronig analysis. The experimentally obtained conductivity spectra are analyzed by considering the contribution from quasiparticles in vortices and also from the vortex dynamics. To include the local-field effect in the high-frequency electromagnetic responses of mixed-state superconductors, we combined the Maxwell-Garnett theory with a self-consistent two-fluid model and obtained the expression for the effective conductivity. The volume fraction of the vortices shows the linear dependence on the applied magnetic field, as expected for s -wave superconductors, by taking into account the flux-flow resistivity.

Original languageEnglish
Article number174525
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume79
Issue number17
DOIs
Publication statusPublished - 2009 May 1

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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