TY - JOUR
T1 - Vortex dynamics in a NbN film studied by terahertz spectroscopy
AU - Ikebe, Y.
AU - Shimano, R.
AU - Ikeda, M.
AU - Fukumura, T.
AU - Kawasaki, M.
PY - 2009/5/1
Y1 - 2009/5/1
N2 - 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.
AB - 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.
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U2 - 10.1103/PhysRevB.79.174525
DO - 10.1103/PhysRevB.79.174525
M3 - Article
AN - SCOPUS:67649133397
SN - 1098-0121
VL - 79
JO - Physical Review B - Condensed Matter and Materials Physics
JF - Physical Review B - Condensed Matter and Materials Physics
IS - 17
M1 - 174525
ER -