Reducing two-level systems dissipations in 3D superconducting niobium resonators by atomic layer deposition and high temperature heat treatment

Applied Physics Letters, Journal Year: 2024, Volume and Issue: 124(13)

Published: March 25, 2024

Superconducting qubits have arisen as a leading technology platform for quantum computing, which is on the verge of revolutionizing world's calculation capacities. Nonetheless, fabrication computationally reliable qubit circuits requires increasing coherence lifetimes, are predominantly limited by dissipations two-level system defects present in thin superconducting film and adjacent dielectric regions. In this paper, we demonstrate reduction losses three-dimensional radio frequency niobium resonators atomic layer deposition 10 nm aluminum oxide Al2O3 films, followed high vacuum heat treatment at 650 °C few hours. By probing effect several treatments Al2O3-coated samples x-ray photoelectron spectroscopy plus scanning conventional resolution transmission electron microscopy coupled with energy loss dispersive spectroscopy, witness dissolution native oxides modification Al2O3-Nb interface, correlates enhancement quality factor low fields two 1.3 GHz cavities coated Al2O3.

Language: Английский

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Circle fit optimization for resonator quality factor measurements: Point redistribution for maximal accuracy

Physical Review Research, Journal Year: 2024, Volume and Issue: 6(1)

Published: March 27, 2024

The control of material loss mechanisms is playing an increasingly important role for improving coherence times superconducting quantum devices. Such losses can be characterized through the measurement planar resonators, which reflect resonance's quality factor ${Q}_{l}$. resonance consists both internal (material) as well coupling when photons escape back into circuit. combined are then described ${Q}_{l}^{\ensuremath{-}1}=\mathrm{Re}{{Q}_{c}^{\ensuremath{-}1}}+{Q}_{i}^{\ensuremath{-}1}$, where ${Q}_{c}$ and ${Q}_{i}$ factors resonator, respectively. To separate relative contributions to ${Q}_{l}$, diameter-correcting circle fits use algebraic or geometric means fit signal on complex plane. However, such produce varied results, so address this issue, we a combination simulation experiment determine reliability fitting algorithm across wide range values from ${Q}_{i}\ensuremath{\ll}{Q}_{c}$ ${Q}_{c}\ensuremath{\ll}{Q}_{i}$. In addition, develop protocol that not only reduce errors by $\ensuremath{\gtrsim}2$ but also mitigates influence background results. This technique generalized other systems beyond resonators.

Language: Английский

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Low-loss α-tantalum coplanar waveguide resonators on silicon wafers: fabrication, characterization and surface modification

Materials for Quantum Technology, Journal Year: 2024, Volume and Issue: 4(2), P. 025801 - 025801

Published: May 14, 2024

Abstract The performance of state-of-the-art superconducting quantum devices is currently limited by microwave dielectric loss at different interfaces. α -tantalum a superconductor that has proven effective in reducing and improving device due to its thin low-loss oxide. Here, we demonstrate the fabrication high-quality factor coplanar-waveguide resonators directly on pristine 300 mm silicon wafers over variety metal deposition conditions perform comprehensive material electrical characterization study. Additionally, apply surface treatment based hydrofluoric acid allows us modify surfaces, leading reduction two-level system three. This can be entirely attributed removal oxides. Our study indicates large scale manufacturing circuits should indeed feasible suggests viable avenue materials-driven advancements circuit performance.

Language: Английский

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High-Coherence Kerr-Cat Qubit in 2D Architecture

Physical Review X, Journal Year: 2024, Volume and Issue: 14(4)

Published: Nov. 20, 2024

The Kerr-cat qubit is a bosonic in which multiphoton Schrödinger cat states are stabilized by applying two-photon drive to an oscillator with Kerr nonlinearity. suppressed bit-flip rate increasing size makes this promising candidate implement quantum error correction codes tailored for noise-biased qubits. However, achieving strong light-matter interactions necessary stabilizing and controlling has traditionally required microwave drives that heat the degrade its performance. In contrast, coupling port removes need at expense of large Purcell decay. By integrating effective band-block filter on chip, we overcome trade-off realize scalable 2D superconducting circuit high coherence. This provides 30 dB isolation frequency negligible attenuation frequencies stabilization readout. We experimentally demonstrate nondemolition readout fidelity 99.6% eight photons. Also, have high-fidelity universal control over qubit, combine fast Rabi oscillations new demonstration X(π/2) gate through phase modulation drive. Finally, lifetime architecture examined as function up ten photons oscillator, time higher than 1 ms only linear increase phase-flip rate, good agreement theoretical analysis circuit. Our shows promise building block fault-tolerant processors small footprint. Published American Physical Society 2024

Language: Английский

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Superconducting flip-chip devices using indium microspheres on Au-passivated Nb or NbN as under-bump metallization layer

Applied Physics Letters, Journal Year: 2025, Volume and Issue: 126(2)

Published: Jan. 13, 2025

Superconducting flip-chip interconnects are crucial for the three-dimensional integration of superconducting circuits in sensing and quantum technology applications. We demonstrate a simplified approach device using commercially available indium microspheres an in-house-built transfer stage bonding two chips patterned with thin films. use gold-passivated niobium or nitride layer as under-bump metallization (UBM) between aluminum-based wiring interconnect. At millikelvin temperatures, our assembly can transport supercurrent tens milliamperes, limited by smallest geometric feature size critical current density UBM not show that pressed interconnect itself carry exceeding 1 A due to its large about 500 μm diameter. Our does require neither electroplating nor patterning indium. The process need bonder be realized top chip transparency through-vias alignment. These devices utilized applications few carrying currents at temperatures.

Language: Английский

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Hydrogen and deuterium tunneling in niobium

Physical review. B./Physical review. B, Journal Year: 2025, Volume and Issue: 111(2)

Published: Jan. 21, 2025

We use density functional methods to identify the atomic configurations of H and D atoms trapped by O impurities embedded in bulk Nb. The are located at octahedral position Nb body-centered cubic (BCC) lattice, (D) tunnel between two degenerate tetrahedral sites separated a mirror plane. Using nudged elastic band (NEB) methods, we calculate double-well potential for O-H O-D wave functions splittings atoms. Our results agree with those obtained from analysis heat capacity neutron scattering measurements on low concentrations O-D. Published American Physical Society 2025

Language: Английский

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Exploring van der Waals Cuprate Superconductors Using a Hybrid Microwave Circuit

Nano Letters, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 27, 2025

The advent of two-dimensional van der Waals materials is a frontier condensed matter physics and quantum devices. However, characterizing such remains challenging due to the limitations bulk material techniques, necessitating development specialized methods. Here, we investigate superconducting properties Bi2Sr2CaCu2O8+x flakes by integrating them with hybrid microwave resonator. resonator significantly modified interaction flake while maintaining high quality factor (3 × 104). We also observe significant upshift frequency increasing temperature, as well positive nonlinearity. These effects originate from presently unknown microscopic mechanism within flake, can be modeled two-level system bath interacting resonant mode. Our findings open path for circuits exploring novel developing new devices technology.

Language: Английский

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Tantalum airbridges for scalable superconducting quantum processors

npj Quantum Information, Journal Year: 2025, Volume and Issue: 11(1)

Published: Jan. 29, 2025

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Implementation of scalable suspended superinductors

Applied Physics Letters, Journal Year: 2025, Volume and Issue: 126(4)

Published: Jan. 27, 2025

Superinductors have become a crucial component in the superconducting circuit toolbox, playing key role development of more robust qubits. Enhancing performance these devices can be achieved by suspending superinductors from substrate, thereby reducing stray capacitance. Here, we present fabrication framework for constructing circuits with suspended planar architectures. To validate effectiveness this process, systematically characterize both resonators and qubits arrays Josephson junctions, ultimately confirming high quality superinductive elements. In addition, process is broadly compatible other types designs. Our results not only pave way scalable architectures utilizing but also provide primitive future investigation loss mechanisms associated device substrate.

Language: Английский

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Why superconducting Ta qubits have fewer tunneling two-level systems at the vacuum-oxide interface than Nb qubits

Physical Review Applied, Journal Year: 2025, Volume and Issue: 23(2)

Published: Feb. 6, 2025

Language: Английский

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