Relaxation of the resistive superconducting state in boron-doped diamond films

Кардакова, А. И.; Shishkin, Andrey G.; Semenov, A.; Gol’tsman, G.; Ryabchun, S. A.; Klapwijk, T. M.; Bousquet, J; Eon, David; Sacépé, Benjamin; Klein, Thierry; Bustarret, Étienne

doi:10.1103/physrevb.93.064506

Cited by 12 publications

(20 citation statements)

References 58 publications

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“…3 are sizeable deviations for the two lowest magnetic fields, for which we find that the Tdependence becomes considerably stronger at B → 0. In this respect, our observation are reminiscent of the B = 0 peculiarities of the relaxation time observed long ago in dirty Nb films [32] and more recently in borondoped diamond films [15] by the AMAR technique. The origin of this puzzling behavior was associated [15] with the longitudinal relaxation time in non-equilibrium superconductivity [33].…”

Section: Resultssupporting

confidence: 70%

“…In this respect, our observation are reminiscent of the B = 0 peculiarities of the relaxation time observed long ago in dirty Nb films [32] and more recently in borondoped diamond films [15] by the AMAR technique. The origin of this puzzling behavior was associated [15] with the longitudinal relaxation time in non-equilibrium superconductivity [33]. This physics is certainly beyond the applicability of our two-temperature model, therefore the corresponding two datasets in Fig.…”

Section: Resultssupporting

confidence: 70%

“…In particular, it is not clear at present, whether the deviations of Z(T ) around B = 0 from the general trend Z ∝ T −3 in Fig. 3 capture the real changes in Z or manifest a failure of the twotemperature model caused, e.g., by the non-equilibrium phenomena [15] or by the vicinity of the BKT transition.…”

Section: Discussionmentioning

confidence: 88%

“…With certain reservations (see section II D for the details), one can neglect the spatially inhomogeneous nature of the photon absorption and assume a uniform, yet different, temperatures for the electrons, T e , and for the (acoustic) phonons, T ph . The radiation energy is absorbed by the electrons and transfered to the substrate within a time called the energy relaxation time, that can be measured via amplitude-modulated absorption of the THz radiation (AMAR) [15]. This method has been first introduced by Gershenzon et al [16] and since then applied to various superconducting materials with different Tdependences of the relaxation time, for instance T −2 in Nb [16] and in boron-doped diamond [15], T −1.6 in NbN [17,18] and T −3 in TiN [19], in NbC [20] and WSi [21] films.…”

Section: Methods and Experimental Detailsmentioning

confidence: 99%

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Thermal Properties of NbN Single-Photon Detectors

et al. 2018

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We investigate thermal properties of a NbN single-photon detector capable of unit internal detection efficiency. Using an independent calibration of the coupling losses we determine the absolute optical power absorbed by the NbN film and, via a resistive superconductor thermometry, the thermal resistance Z(T ) of the NbN film in dependence of temperature. In principle, this approach permits a simultaneous measurement of the electron-phonon and phonon-escape contributions to the energy relaxation, which in our case is ambiguous for their similar temperature dependencies. We analyze the Z(T ) within the two-temperature model and impose an upper bound on the ratio of electron and phonon heat capacities in NbN, which is surprisingly close to a recent theoretical lower bound for the same quantity in similar devices.

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Section: Resultssupporting

confidence: 70%

Section: Resultssupporting

confidence: 70%

Section: Discussionmentioning

confidence: 88%

Section: Methods and Experimental Detailsmentioning

confidence: 99%

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Thermal Properties of NbN Single-Photon Detectors

et al. 2018

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“…Correspondingly, the main objective of this paper is the theoretical and experimental study of the mechanisms of electron-phonon interaction and the energy exchange between ultra-thin metal films and dielectric substrates. Experiments were performed on WSi film grown on Si/SiO 2 substrate with the use of the direct technique of amplitude-modulated absorption of sub-THz radiation (AMAR) [26][27][28]. We show that WSi film on Si/SiO 2 substrate is the perfect example of an important class of acoustically soft ultra-thin films on rigid substrates, with a strong internal phonon bottleneck effect.…”

Section: Introductionmentioning

confidence: 99%

Nonbolometric bottleneck in electron-phonon relaxation in ultrathin WSi films

Sidorova¹,

Kozorezov

Semenov

et al. 2018

Phys. Rev. B

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We developed the model of internal phonon bottleneck to describe the energy exchange between the acoustically soft ultra-thin metal film and acoustically rigid substrate. Discriminating phonons in the film into two groups, escaping and non-escaping, we show that electrons and non-escaping phonons may form a unified subsystem, which is cooled down only due to interactions with escaping phonons, either due to direct phonon conversion or indirect sequential interaction with an electronic system. Using an amplitude-modulated absorption of the sub-THz radiation technique, we studied electron-phonon relaxation in ultra-thin disordered films of tungsten silicide. We found an experimental proof of the internal phonon bottleneck. The experiment and simulation based on the proposed model agree well, resulting in e−ph~ 140-190 ps at C = 3.4 K supporting the results of earlier measurements by independent techniques. downslide, until the excited volume containing highly non-equilibrium quasiparticles and phonons, termed as a hotspot, is formed [15]. The details of this process play an important role in SNSPDs and were the focus of recent work [18], where the dominant role of electron-phonon interactions over electron-electron interactions was emphasized even in strongly disordered NbN and WSi where electron-electron interaction is strongly enhanced. Another aspect of hotspot formation is phonon loss into a substrate, defining energy density and hence equilibration rates [18] and fluctuations [19]. The energy exchange between the film and the substrate controls the nucleation and growth of normal domain, resulting in photon count. The latter is also influenced by the strength of electron-phonon, phonon-electron interactions and phonon escape from the film. For this reason, studying electron-phonon interaction and cooling of non-equilibrium electron and phonon distributions in materials, which are used for radiation detection is one of the central problems for all sensors.A new class of amorphous superconductors for SNSPDs, and in the first instance WSi, attracted immediate attention. Subsequently, electron-phonon interaction in WSi was studied by applying pump probe [20] and magnetoconductance [21] measurements, while the detection mechanism was investigated with quantum detector tomography [22]. The experimental work [20] utilised a time resolved two-photon detection technique to study the evolution of the hotspot in current-carrying nanowire under the conditions that the nanowire remains superconducting. Relaxation times of the order of hundreds of picoseconds were found and interpreted in [23] using the kinetic model of hotspot relaxation, where self-recombination of non-equilibrium quasiparticles plays a dominant role. The characteristic electron-phonon time 0 [24], which depends on material, was found to be 0.84 -1.0 ns [20] for tungsten rich WSi. . Thus, electron-phonon relaxation in WSi turned out to be slow in comparison with conventional SNSPD materials, such as NbN and NbTiN (where the measured time of relaxation of ...

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