Recombination Time of Quasiparticles in Superconducting Aluminum

Levine, James L.; Hsieh, Shelly

doi:10.1103/physrevlett.20.994

Cited by 45 publications

(19 citation statements)

References 7 publications

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“…The steady state measurements of Miller and Dayem Ell], Levine and Hsie [12] using AI-I-A1-Mn sandwich structures on A120 3 crystals substrates in direct contact with liquid 3He are more difficult to compare with the phonon escape model than the experiments of Gray et al [13], and Long [14] which have been performed with AI-I-A1 junctions on A1203 crystals in vacuum. For the latter sample configuration we used the data listed in Tables 1 and 2 for calculating %ff in the thickness ranges d~Aw and d>Aw according to (1) and (2) …”

Section: Aluminummentioning

confidence: 80%

“…In the limit of d small compared to the phonon reabsorption mean free path A w only the limiting angles of total phonon reflection q~m,x at the film boundaries determine the phonon trapping factor or the ratio "~eff/'~R with zR the intrinsic or true quasiparticle decay time without phonon trapping. Experimental data for A1 on A1203 substrates [14,11,12] with different outer surface conditions in this film thickness range scatter between "~eff ='ER and "~eff ~-7'ZR" The trapping factor of 7 is calculated from the limiting angle of total reflection at the A1-A1203 boundary without contact to liquid He. Further results are listed ha Experimental data for A1 on A1203 [14] and Sn on Si [9,25] agree with the constant of proportionality calculated from the model by use of the phonon and electron densities of state and the phonon escape rate across the film-substrate boundary, as obtained from acoustical data (see Table II).…”

Section: Conclusion and Summarymentioning

confidence: 99%

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Intrinsic and experimental quasiparticle recombination times in superconducting films

et al. 1977

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Abstract. Experimental quasiparticle recombination lifetime data for superconducting A1, Sn, and Pb films are compared with calculations based on a ray acoustic model taking account of the film thickness dependence of the reabsorption of recombination phonons. Information on the true or intrinsic quasiparticle recombination lifetime obtained from these and other data is discussed. PACS Code: 74The apparent recombination decay time raf of quasiparticles in superconducting films depends strongly on the reabsorption of phonons emitted in recombination. This influence has been treated in terms of a ray acoustical model [1] for phonon absorption and transmission to the film substrate. In the present article we compare this model with available experimental data. In Sec. 1 we discuss the results of the model calculation, in Sec. 2 possibilities of estimating the important quantity Aw, the phonon reabsorption mean free path. In Sec. 3 experimental %ff data for A1, Sn, and Pb are compared with calculation, together with a discussion of presently available z g data. Results of the Phonon Trapping ModelThe influence of phonon reabsorption can be discussed in terms of three physically significant ranges of the thickness dependence of %ff.

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Section: Aluminummentioning

confidence: 80%

Section: Conclusion and Summarymentioning

confidence: 99%

Intrinsic and experimental quasiparticle recombination times in superconducting films

et al. 1977

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“…7,8,9,10,11 In these steadystate measurements, the excited state is detected through an average response that deviates from equilibrium and the effective pair relaxation time is inferred, assuming that the process has a simple exponential decay.…”

Section: Introductionmentioning

confidence: 99%

Photoinduced time-resolved electrodynamics of superconducting metals and alloys

et al. 2005

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The photoexcited state in superconducting metals and alloys was studied via pump-probe spectroscopy. A pulsed Ti:sapphire laser was used to create the non-equilibrium state and the far-infrared pulses of a synchrotron storage ring, to which the laser is synchronized, measured the changes in the material optical properties. Both the time-and frequency-dependent photoinduced spectra of Pb, Nb, NbN, Nb0.5Ti0.5N, and Pb0.75Bi0.25 superconducting thin films were measured in the low-fluence regime. The time dependent data establish the regions where the relaxation rate is dominated either by the phonon escape time (phonon bottleneck effect) or by the intrinsic quasiparticle recombination time. The photoinduced spectra measure directly the reduction of the superconducting gap due to an excess number of quasiparticles created by the short laser pulses. This gap shift allows us to establish the temperature range over which the low fluence approximation is valid.

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“…Thermally excited quasiparticles with energies E>A decay to the ground state within a characteristic time ~R via the formation of Cooper-pairs and the emission of phonons of the energy hco>2A. Whereas ~R, the intrinsic recombination time, is not directly accessible by experiment, an effective time constant rexp can be determined from the decay of an excess quasiparticle concentration generated by an external dynamic creation mechanism, such as pair breaking by the absorption of phonons [1,2] or photons or by tunneling between superconductors [7][8][9][10][11][12][13][14][15]. As has been shown in several experimental [1-5, 10, 12-15] and theoretical [-10, 16, 171 investigations, rex p significantly exceeds rR by the trapping of recombination phonons via repeated reabsorption and * Future address: IBM Ziirich, Research Laboratory, CH-8803 Riischlikon, Switzerland emission of 2A-phonons within the superconducting device.…”

Section: Introductionmentioning

confidence: 99%

Quasiparticle recombination time in superconducting tin and normal electronic density of states at the fermi surface from tunnel junction experiments

1978

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We have measured the temperature dependence of the effective quasiparticle recombination time in superconducting tin tunnel junctions by current and laser pulse excitation. The experimental times show satisfactory agreement with calculations based on the ray acoustic lifetime model of Eisenmenger et al. taking into account the film thickness dependence of the phonon reabsorption, 2A-phonon volume loss processes and phonon transmission from the junction into the substrate and liquid helium. On the basis of the BCS density of thermally excited quasiparticles and simplified rate equations for quasiparticle recombination, and from the analysis of measurements of decaying excess quasiparticle concentrations we obtain a mean value N o =(2.73_+0.03) 1022 eV-1 cm-3 for the electronic density of states at the Fermi Surface in thin, evaporated tin films. This value differs less than 5 % from that obtained from the experimental electronic heatcapacity coefficient of the bulk material.

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Recombination Time of Quasiparticles in Superconducting Aluminum

Cited by 45 publications

References 7 publications

Intrinsic and experimental quasiparticle recombination times in superconducting films

Intrinsic and experimental quasiparticle recombination times in superconducting films

Photoinduced time-resolved electrodynamics of superconducting metals and alloys

Quasiparticle recombination time in superconducting tin and normal electronic density of states at the fermi surface from tunnel junction experiments

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