Quasiparticle and phonon lifetimes in superconductors

Kaplan, Steven B.; C., C.; Langenberg, D. N.; Chang, Joon-Hyuk; Jafarey, S.; Scalapino, D. J.

doi:10.1103/physrevb.14.4854

Cited by 856 publications

(609 citation statements)

References 58 publications

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“…⌫, on the other hand, remains zero except at temperatures very close to the transition temperature of the superconductor, where it shows a slight increase. This slight increase is in qualitative agreement with the intrinsic decrease of the quasiparticle lifetime of the superconductor as theoretically predicted, 35 and experimentally observed in strong-coupling superconductors. 36,37 Figure 6͑a͒ shows the PCAR spectra on the CaFe 4 Sb 12 .…”

Section: Resultssupporting

confidence: 90%

Temperature dependence of transport spin polarization inNdNi5from point-contact Andreev reflection

et al. 2007

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We report a study in which point-contact Andreev reflection ͑PCAR͒ spectroscopy using a superconducting Nb tip has been carried out on NdNi 5 , a ferromagnet with a Curie temperature of T C ϳ 7.7 K. The measurements were performed over a temperature range of 2 -9 K, which spans across the ferromagnetic transition temperature. From an analysis of the spectra, we show that ͑i͒ the temperature dependence of the extracted value of transport spin polarization closely follows the temperature dependence of the spontaneous magnetization; ͑ii͒ the superconducting quasiparticle lifetime shows a large decrease close to the Curie temperature of the ferromagnet. We attribute the latter to the presence of strong ferromagnetic spin fluctuations in the ferromagnet close to the ferromagnetic transition temperature.

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Section: Resultssupporting

confidence: 90%

Temperature dependence of transport spin polarization inNdNi5from point-contact Andreev reflection

et al. 2007

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“…[18][19][20] The QP population is typically modeled in terms of a diffusion equation, describing their recombination retarded by phonon retrapping, and other loss mechanisms. [21][22][23][24][25] Converting the excess density into an effective, position-dependent temperature T (x), one finds 26,27 that at phonon temperatures k B T the S leads can be overheated on a length scale ranging from tens of micrometers to a millimeter, as the electron-phonon relaxation and electronic heat conduction are exponentially suppressed compared to their normal-state values. 22,28 Experiment.…”

mentioning

confidence: 99%

“…[21][22][23][24][25] Converting the excess density into an effective, position-dependent temperature T (x), one finds 26,27 that at phonon temperatures k B T the S leads can be overheated on a length scale ranging from tens of micrometers to a millimeter, as the electron-phonon relaxation and electronic heat conduction are exponentially suppressed compared to their normal-state values. 22,28 Experiment. Here we present data from one of several measured symmetric SINIS structures similar to that shown in Fig.…”

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confidence: 99%

Magnetic-field-induced stabilization of nonequilibrium superconductivity in a normal-metal/insulator/superconductor junction

Peltonen¹,

Muhonen

Meschke³

et al. 2011

Phys. Rev. B

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A small magnetic field is found to enhance relaxation processes in a superconductor, thus stabilizing superconductivity in nonequilibrium conditions. In a normal-metal (N)/insulator/superconductor (S) tunnel junction, applying a field of the order of 100 μT leads to significantly improved cooling of the N island by quasiparticle (QP) tunneling. These findings are attributed to faster QP relaxation within the S electrodes as a result of enhanced QP drain through regions with a locally suppressed energy gap due to magnetic vortices in the S leads at some distance from the junction. Introduction. In this Rapid Communication, we report an observation that appears counterintuitive at first: A small magnetic field is found to stabilize superconductivity under quasiparticle (QP) injection. In our experiment, the cooling power of normal-metal (N)/insulator (I)/superconductor (S) tunnel structures is enhanced in perpendicular magnetic fields B ⊥ 100 μT = 1 G. A measured maximum temperature drop δT relative to a starting bath temperature T 0 = 285 mK exhibiting this behavior is shown in Fig. 1(a). The improvement is unexpected, as in general the effect of a magnetic field is to suppress superconductivity. Electronic cooling in NIS junctions in the presence of magnetic fields in both perpendicular and parallel orientations has been studied before, 1 but only in higher fields where the cooling power was already reduced due to a diminishing superconducting energy gap . On the other hand, the creation of magnetic vortices 2 has been shown to enhance QP relaxation in superconducting aluminum, as the QPs become trapped and thermalize in the regions of a reduced energy gap. 3 Here we demonstrate that the additional relaxation channel due to an enhanced QP drain through regions occupied by magnetic vortices enhances the superconducting performance of S leads and improves the electronic cooling in NIS junctions. This can be of relevance in superconducting qubits, 4-7 resonators, 8 and in hybrid SINIS turnstiles 9 in reducing the effects from nonequilibrium and residual QPs arising due to drive and microwave radiation from the environment. Moreover, improved relaxation caused by vortex creation in the S leads can partially explain the "reentrant superconductivity" observed in Zn and Al nanowires. 10,11 In the present case, as sketched in Fig. 1(a), vortex formation in the S electrodes away from the NIS junction improves relaxation of the injected QPs and leads to enhanced cooling of the N island. In higher fields, vortices move closer to the junction, deteriorating the cooling power.In a NIS junction, acts as an energy filter for the tunneling QP. [12][13][14][15] At low temperatures k B T and for bias voltages eV across the junction, the electrons in the N electrode cool considerably below the phonon temperature by hot QP extraction. The effect can be made to be more pronounced in a symmetric double-junction SINIS structure with a small N

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“…[85]. The labeled lines present the pair-breaking rate at various phonon energies, described in units of the material-specific superconducting gap.…”

Section: Simulations Qp Cascadementioning

confidence: 99%

“…The third option uses a quasiparticle cascade model developed in [85,86,87,88]. The model is described in detail below.…”

Section: Qpts In the Dmcmentioning

confidence: 99%

Detector Simulation and WIMP Search Analysis for the Cryogenic Dark Matter Search Experiment

McCarthy¹

2013

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Astrophysical and cosmological measurements on the scales of galaxies, galaxy clusters, and the universe indicate that ∼85% of the matter in the universe is composed of dark matter, made up of non-baryonic particles that interact with cross-sections on the weak scale or lower. Hypothetical Weakly Interacting Massive Particles, or WIMPs, represent a potential solution to the dark matter problem, and naturally arise in certain Standard Model extensions.The Cryogenic Dark Matter Search (CDMS) collaboration aims to detect the scattering of WIMP particles from nuclei in terrestrial detectors. Germanium and silicon particle detectors are deployed in the Soudan Underground Laboratory in Minnesota. These detectors are instrumented with phonon and ionization sensors, which allows for discrimination against electromagnetic backgrounds, which strike the detector at rates orders of magnitude higher than the expected WIMP signal.This dissertation presents the development of numerical models of the physics of the CDMS detectors, implemented in a computational package collectively known as the CDMS Detector Monte Carlo (DMC). After substantial validation of the models against data, the DMC is used to investigate potential backgrounds to the next iteration of the CDMS experiment, known as SuperCDMS. Finally, an investigation of using the DMC in a reverse Monte Carlo analysis of WIMP search data is presented.140.23 kg-days of WIMP search data from the silicon detectors in the CDMSII experiment is also analyzed. The resulting upper limits on the WIMP-nucleon crosssection are higher than those published by other experiments at all WIMP masses, and the lowest limit on the WIMP-nucleon cross-section is 1.07*10 −42 cm 2 at a mass 3 of 60 GeV/c 2 . These results do provide new and interesting constraints at WIMP masses ≤40 GeV/c 2 and cross sections from 10 −42 -10 −39 cm 2 , a region in which some WIMP search experiments have claimed evidence for a WIMP signal, which other experiments claim to have ruled out.

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Quasiparticle and phonon lifetimes in superconductors

Cited by 856 publications

References 58 publications

Temperature dependence of transport spin polarization inNdNi5from point-contact Andreev reflection

Temperature dependence of transport spin polarization inNdNi5from point-contact Andreev reflection

Magnetic-field-induced stabilization of nonequilibrium superconductivity in a normal-metal/insulator/superconductor junction

Detector Simulation and WIMP Search Analysis for the Cryogenic Dark Matter Search Experiment

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