Superconducting Resonators Based on TiN/Tapering/NbN/Tapering/TiN Heterostructures

Tang, Yongchao; Zhang, Hui; Kwon, Sangil; Mohebbi, Hamid Reza; Cory, David G.; Peng, Licong; Gu, Lin; Guo, Haizhong; Jin, Kuijuan; Miao, Guo‐Xing

doi:10.1002/adem.201600226

Cited by 4 publications

(3 citation statements)

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“…Titanium nitride (TiN) thin films exhibit good chemical stability down to nanometer thickness [14] and are used in the fabrication of superconducting devices for photon detection [15] and for quantum information processing [16][17][18][19]. Low dielectric losses at microwave frequencies observed in TiN films are associated with a relatively small surface density of two-level systems defects that contribute to decoherence of the resonators and qubits [20][21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Superconductivity Behavior in Epitaxial TiN Films Points to Surface Magnetic Disorder

et al. 2019

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We analyze the evolution of the normal and superconducting electronic properties in epitaxial TiN films, characterized by high Ioffe-Regel parameter values, as a function of the film thickness. As the film thickness decreases, we observe an increase of the residual resistivity, which becomes dominated by diffusive surface scattering for d ≤ 20 nm. At the same time, a substantial thicknessdependent reduction of the superconducting critical temperature is observed compared to the bulk TiN value. In such a high quality material films, this effect can be explained by a weak magnetic disorder residing in the surface layer with a characteristic magnetic defect density of ∼ 10 12 cm −2 . Our results suggest that surface magnetic disorder is generally present in oxidized TiN films. arXiv:1903.05009v3 [cond-mat.mtrl-sci]

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Section: Introductionmentioning

confidence: 99%

Superconductivity Behavior in Epitaxial TiN Films Points to Surface Magnetic Disorder

et al. 2019

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“…Fully epitaxial Al (111) should display three-fold symmetry in the ϕ -scan of (200) planes. The appearance of six peaks indicates two symmetrically equivalent growth orientations (twins) occur in the Al layers, as a result of stacking three-fold symmetric fcc structures onto the six-fold symmetric hcp substrate 34 . The lower panel of Fig.…”

Section: Methodsmentioning

confidence: 99%

Phonon engineering in proximity enhanced superconductor heterostructures

Tang

Kwon

Mohebbi

et al. 2017

Sci Rep

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In this research, we tailor the phonon density of states (DOS) in thin superconducting films to suppress quasiparticle losses. We examine a model system of a proximity-enhanced three-layered Al/Nb/Al heterostructure and show that the local quantized phonon spectrum of the ultrathin Al cladding layers in the heterostructure has a pronounced effect on the superconducting resonator’s quality factors. Instead of a monotonic increase of quality factors with decreasing temperatures, we observe the quality factor reaches a maximum at 1.2 K in 5/50/5 nm Al/Nb/Al microstrip resonators, because of a quantized phonon ladder. The phonon DOS may be engineered to enhance the performance of quantum devices.

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“…Maintaining a high quality factor is not straightforward in a magnetic field because of magnetic field depena) Electronic mail: kwon2866@gmail.com dent microwave losses. [36][37][38][39][40][41][42][43][44][45][46][47][48][49] The focus of this paper is to develop experimental methods to understand and characterize the magnetic field dependent loss mechanisms, quasiparticle generation and current-induced motion of vortices.…”

Section: Introductionmentioning

confidence: 99%

Magnetic field dependent microwave losses in superconducting niobium microstrip resonators

Kwon

Roudsari

Benningshof

et al. 2018

Journal of Applied Physics

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We describe an experimental protocol to characterize magnetic field dependent microwave losses in superconducting niobium microstrip resonators. Our approach provides a unified view that covers two well-known magnetic field dependent loss mechanisms: quasiparticle generation and vortex motion. We find that quasiparticle generation is the dominant loss mechanism for parallel magnetic fields. For perpendicular fields, the dominant loss mechanism is vortex motion or switches from quasiparticle generation to vortex motion, depending on cooling procedures. In particular, we introduce a plot of the quality factor versus the resonance frequency as a general method for identifying the dominant loss mechanism. We calculate the expected resonance frequency and the quality factor as a function of the magnetic field by modeling the complex resistivity. Key parameters characterizing microwave loss are estimated from comparisons of the observed and expected resonator properties. Based on these key parameters, we find a niobium resonator whose thickness is similar to its penetration depth is the best choice for X-band electron spin resonance applications. Finally, we detect partial release of the Meissner current at the vortex penetration field, suggesting that the interaction between vortices and the Meissner current near the edges is essential to understand the magnetic field dependence of the resonator properties.

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Superconducting Resonators Based on TiN/Tapering/NbN/Tapering/TiN Heterostructures

Cited by 4 publications

References 40 publications

Superconductivity Behavior in Epitaxial TiN Films Points to Surface Magnetic Disorder

Superconductivity Behavior in Epitaxial TiN Films Points to Surface Magnetic Disorder

Phonon engineering in proximity enhanced superconductor heterostructures

Magnetic field dependent microwave losses in superconducting niobium microstrip resonators

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