Superconducting phase transitions in ultrathin TiN films

Baturina, T. I.; Postolova, S. V.; Mironov, Andrey E.; Glatz, Andreas; Baklanov, Mikhaı̈l R.; Vinokur, V. M.

doi:10.1209/0295-5075/97/17012

Cited by 62 publications

(103 citation statements)

References 46 publications

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“…The magnetic field was applied perpendicular to the film surface. Transport and superconducting properties of our sample are close to those used in earlier studies 12,35 . The sample parameters are as follows: the diffusion constant D ¼ 0.32 cm 2 s À 1 , the superconducting coherence length x(0) ¼ 9.3 nm, the transition temperature, Shown in the Supplementary Fig.…”

Section: Methodssupporting

confidence: 79%

“…These oscillations are characteristic to 2D Josephson junction arrays, proximity-effect junction arrays and superconducting wire networks, and reflect the collective behaviour and effect of synchronization of the Josephson phases in 2D multiconnected superconducting systems, for detailed discussion see ref. 35. Supplementary Figure S1b shows the I-V characteristic in a log-log scale and the inset presents the same data as the differential resistance dV/ dI versus I plot at zero magnetic field and T ¼ 0.1 K. Using the magnitude of the critical current evaluated from the position of the maximum of the dV/dI versus I curve 35 , we have determined the critical current through the whole network I c ¼ 0.17 mA, yielding the critical current i c ¼ 0.68 nA per one constriction.…”

Section: Methodsmentioning

confidence: 99%

“…35. Supplementary Figure S1b shows the I-V characteristic in a log-log scale and the inset presents the same data as the differential resistance dV/ dI versus I plot at zero magnetic field and T ¼ 0.1 K. Using the magnitude of the critical current evaluated from the position of the maximum of the dV/dI versus I curve 35 , we have determined the critical current through the whole network I c ¼ 0.17 mA, yielding the critical current i c ¼ 0.68 nA per one constriction. Having determined the critical current, one estimates the Pearl penetration depth l > ¼ :/ (2em 0 i c ) ¼ 38 cm, and the Josephson coupling E j ¼ (:i c /2e).…”

Section: Methodsmentioning

confidence: 99%

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Magnetic field-induced dissipation-free state in superconducting nanostructures

et al. 2013

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A superconductor in a magnetic field acquires a finite electrical resistance caused by vortex motion. A quest to immobilize vortices and recover zero resistance at high fields made intense studies of vortex pinning one of the mainstreams of superconducting research. Yet, the decades of efforts resulted in a realization that even promising nanostructures, utilizing vortex matching, cannot withstand high vortex density at large magnetic fields. Here, we report a giant reentrance of vortex pinning induced by increasing magnetic field in a W-based nanowire and a TiN-perforated film densely populated with vortices. We find an extended range of zero resistance with vortex motion arrested by self-induced collective traps. The latter emerge due to order parameter suppression by vortices confined in narrow constrictions by surface superconductivity. Our findings show that geometric restrictions can radically change magnetic properties of superconductors and reverse detrimental effects of magnetic field.

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Section: Methodssupporting

confidence: 79%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Magnetic field-induced dissipation-free state in superconducting nanostructures

et al. 2013

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“…We should note that, although R s can usually be measured rather accurately, the thickness, which is measured indirectly, is typically reported with a lower level of confidence [38]. Moreover, although there is an ongoing dispute of how to determine T c in thin films, usually the values for T c are measured in a consistent manner within a data set of a given material, allowing an examination of each data set at least with itself [45]. These data include NbN sets of films that were reported previously by other groups, each of which was reported to be in agreement with one of the models of the form T c (R s ) [17] or T c (d) [18,19].…”

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confidence: 99%

Universal scaling of the critical temperature for thin films near the superconducting-to-insulating transition

et al. 2014

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Thin superconducting films form a unique platform for geometrically confined, strongly interacting electrons. They allow an inherent competition between disorder and superconductivity, which in turn enables the intriguing superconducting-to-insulating transition and is believed to facilitate the comprehension of high-T c superconductivity. Furthermore, understanding thin film superconductivity is technologically essential, e.g., for photodetectors and quantum computers. Consequently, the absence of established universal relationships between critical temperature (T c ), film thickness (d), and sheet resistance (R s ) hinders both our understanding of the onset of the superconductivity and the development of miniaturized superconducting devices. We report that in thin films, superconductivity scales as dT c (R s ). We demonstrated this scaling by analyzing the data published over the past 46 years for different materials (and facilitated this database for further analysis). Moreover, we experimentally confirmed the discovered scaling for NbN films, quantified it with a power law, explored its possible origin, and demonstrated its usefulness for nanometer-length-scale superconducting film-based devices. Relationships between low-temperature and normal-state properties are crucial for understanding superconductivity. For instance, the Bardeen-Cooper-Schrieffer theory (BCS) successfully associates the normal-to-superconducting transition temperature, T c , with material parameters, such as the Debye temperature ( D ) and the density of states at the Fermi level [N (0)]. Hence, the BCS model allows us to infer superconducting characteristics (i.e., T c ) from properties measured at higher temperatures [1]. In the BCS framework, superconductivity occurs when attractive phonon-mediated electron-electron interactions overcome the Coulomb repulsion, giving rise to paired electrons (Cooper pairs) with a binding energy gap:. Moreover, within a superconductor, all Cooper pairs are coupled, giving rise to a collective electron interaction. Such a collective state is described by a complex global order parameter with real amplitude ( ) and phase (ϕ): = e iϕ .Because superconductivity relies on a collective electron behavior, the onset of superconductivity occurs when the number of participating electrons is just enough to be considered collective, i.e., at the nanoscale [2-5]. Thus, it is known that the superconductivity-disorder interplay varies in thin films and is effectively tuned with the film thickness (d) or with the disorder in the system, which is represented by sheet resistance of the film at the normal state (R s ) [6][7][8][9][10]. The mechanism of superconductivity in thin films has been investigated since the 1930s [6] increase in T c with decreasing thickness in aluminum films in a study that pioneered the currently ongoing research of thin superconducting films. This enhancement of T c , which is still not completely understood, was later confirmed by Strongin et al. [12], who also reported the more common be...

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“…[39][40][41][42][43] There has been an academic debate about the nature of this phase transition and the origin of the large negative MR. 12,[44][45][46] Some theories consider a global quantum phase transition 21,33,47,48 or quantum corrections to the classical magnetotransport. 12,24,49,50 Here we report on large negative and positive MR in Ga-rich, p-type Si films and demonstrate that a simple phenomenological model based on local superconductivity and hopping transport can describe the complex temperature and field dependence of the resistance.…”

Section: R(b)−r(0) R(0) R (B) > R (0) Positive Mr R(b)−r(0) R(b)mentioning

confidence: 54%

Large magnetoresistance of insulating silicon films with superconducting nanoprecipitates

2016

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We report on large negative and positive magnetoresistance in inhomogeneous, insulating Si:Ga films below a critical temperature of about 7 K. The magnetoresistance effect exceeds 300 % at temperatures below 3 K and fields of 8 T. The comparison of the transport properties of superconducting samples with that of insulating ones reveals that the large magnetoresistance is associated with the appearance of local superconductivity. A simple phenomenological model based on localized Cooper pairs and hopping quasiparticles is able to describe the temperature and magnetic field dependence of the sheet resistance of such films.

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Superconducting phase transitions in ultrathin TiN films

Cited by 62 publications

References 46 publications

Magnetic field-induced dissipation-free state in superconducting nanostructures

Magnetic field-induced dissipation-free state in superconducting nanostructures

Universal scaling of the critical temperature for thin films near the superconducting-to-insulating transition

Large magnetoresistance of insulating silicon films with superconducting nanoprecipitates

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