Superconductor–Insulator Transition in NbTiN Films

Burdastyh, M. V.; Postolova, S. V.; Baturina, T. I.; Proslier, Thomas; Vinokur, V. M.; Mironov, Andrey E.

doi:10.1134/s0021364017230060

Cited by 10 publications

(3 citation statements)

References 31 publications

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“…Reduction in thickness introduces more disorder 14 , 40 – 42 as that is also evident in the increased R n presented in Figs. 1 b and 2 d. However, relating disorder directly to the resistivity would not be appropriate in the present scenario as there are secondary phases present along with TiN.…”

Section: Resultsmentioning

confidence: 65%

A robust nitridation technique for fabrication of disordered superconducting TiN thin films featuring phase slip events

Yadav¹,

Kaushik²,

Saravanan³

et al. 2021

Sci Rep

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Disorder induced phase slip (PS) events appearing in the current voltage characteristics (IVCs) are reported for two-dimensional TiN thin films produced by a robust substrate mediated nitridation technique. Here, high temperature annealing of Ti/Si3N4 based metal/substrate assembly is the key to produce majority phase TiN accompanied by TiSi2 & elemental Si as minority phases. The method itself introduces different level of disorder intrinsically by tuning the amount of the non-superconducting minority phases that are controlled by annealing temperature (Ta) and the film thickness. The superconducting critical temperature (Tc) strongly depends on Ta and the maximum Tc obtained from the demonstrated technique is about 4.8 K for the thickness range ~ 12 nm and above. Besides, the dynamics of IVCs get modulated by the appearance of intermediated resistive steps for decreased Ta and the steps get more prominent for reduced thickness. Further, the deviation in the temperature dependent critical current (Ic) from the Ginzburg–Landau theoretical limit varies strongly with the thickness. Finally, the Tc, intermediate resistive steps in the IVCs and the depairing current are observed to alter in a similar fashion with Ta and the thickness indicating the robustness of the synthesis process to fabricate disordered nitride-based superconductor.

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Section: Resultsmentioning

confidence: 65%

A robust nitridation technique for fabrication of disordered superconducting TiN thin films featuring phase slip events

Yadav¹,

Kaushik²,

Saravanan³

et al. 2021

Sci Rep

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“…After deviating from the SF-fits, the R ✷ (T ) either saturates (samples from S3-5 to S3-2) like a Bose metal or increases exponentially (S3-1, S3-0) like an insulator (thinner films, not shown in Fig. 1 (c), are insulators 42 ).…”

Section: Suppression Of Superconductivity In Set-3mentioning

confidence: 97%

Superconducting phase transitions in disordered NbTiN films

Burdastyh

Postolova

Proslier

et al. 2020

Sci Rep

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The suppression of superconductivity in disordered systems is a fundamental problem of condensed matter physics. Here we investigate the superconducting niobium-titanium-nitride (Nb 1−x TixN) thin films grown by atomic layer deposition (ALD) where disorder is controlled by the slight tuning of the ALD process parameters. We observe the smooth crossover from the disorderdriven superconductor-normal metal transition (often reffered to as fermionic mechanism) to the case where bosonic mechanism dominates and increasing disorder leads to formation of metal with Cooper pairing. We show that, in 'moderately' disordered films, the transition to zero-resistance state occurs in a full agreement with the conventional theories of superconducting fluctuations and Berezinskii-Kosterlitz-Thouless transition. However, the 'critically' disordered films violate this accord showing low-temperature features possibly indicating the Bose metal phase. We show that it is the interrelation between film's sheet resistance in the maximum, Rmax, of the resistive curve R✷(T ) and Rq = h/4e 2 that distinguishes between these two behaviors. We reveal the characteristic features in magnetoresistance of the 'critically' disordered films with Rmax > Rq. 2/9

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“…NbTiN films of thicknesses d = 15, 20, and 25 nm are grown, varying only the number of ALD cycles 240, 420, and 768 cycles, for S1, S2 and S3 respectively, with all other parameters of the ALD process held constant. Further analysis shows that the NbTiN films are an approximately 7:3 solid solution of NbN and TiN [29].…”

Section: Methodsmentioning

confidence: 99%

Imaging quantum fluctuations near criticality

et al. 2018

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A quantum phase transition (QPT) occurs between two competing phases of matter at zero temperature, driven by quantum fluctuations. Though the presence of these fluctuations is well established, they have not been locally imaged in space and their local dynamics has not been studied so far. We use a scanning superconducting quantum interference device to image quantum fluctuations in the vicinity of the QPT from a superconductor to an insulator. We find fluctuations of the diamagnetic response in both space and time that survive well below the transition temperature, demonstrating their quantum nature. The fluctuations appear as telegraph-like noise with a range of characteristic times and a non-monotonic temperature dependence, revealing unexpected quantum granularity. The lateral dimension of these fluctuations grows towards criticality, offering a new measurable length scale. Our results provide physical insight about the reorganization of phases across a QPT, with implications for any theoretical description. This paves a new route for future quantum information applications.

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Superconductor–Insulator Transition in NbTiN Films

Cited by 10 publications

References 31 publications

A robust nitridation technique for fabrication of disordered superconducting TiN thin films featuring phase slip events

A robust nitridation technique for fabrication of disordered superconducting TiN thin films featuring phase slip events

Superconducting phase transitions in disordered NbTiN films

Imaging quantum fluctuations near criticality

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