A transmon qubit realized by exploiting the superconductor-insulator transition

• URL: http://arxiv.org/abs/2510.19983v1
• Date: Wed, 22 Oct 2025 19:29:01 GMT
• Title: A transmon qubit realized by exploiting the superconductor-insulator transition
• Authors: C. G. L. Bøttcher, E. Önder, T. Connolly, J. Zhao, C. Kvande, D. Q. Wang, P. D. Kurilovich, S. Vaitiekėnas, L. I. Glazman, H. X. Tang, M. H. Devoret,
• Abstract summary: Superconducting qubits are among the most promising platforms for realizing practical quantum computers.<n>In this work, we exploit a thickness-driven superconductor-insulator transition to form a weak link employing only atomic layer deposition and atomic layer etching.<n>We produce a transmon qubit, '$planaron$', with a measured anharmonicity of $alpha/2pi = 235$ MHz; at present, the linewidth is $kappa/2pi = 15 mathrm: MHz$.
• Score: 0.0
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: Superconducting qubits are among the most promising platforms for realizing practical quantum computers. One requirement to create a quantum processor is nonlinearity, which in superconducting circuits is typically achieved by sandwiching a layer of aluminum oxide between two aluminum electrodes to form a Josephson junction. These junctions, however, face several limitations that hinder their scalability: the small superconducting gap of aluminum necessitates millikelvin operating temperatures, the material interfaces lead to dissipation, and the sandwich geometry adds unwelcome capacitance for high-frequency applications. In this work, we address all three limitations using a novel superconducting weak link based on the superconductor-insulator transition. By locally thinning a single film of niobium nitride, we exploit its thickness-driven superconductor-insulator transition to form a weak link employing only atomic layer deposition and atomic layer etching. We utilize our weak links to produce a transmon qubit, '$planaron$', with a measured anharmonicity of $\alpha/2\pi = 235$ MHz; at present, the linewidth is $\kappa/2\pi = 15 \mathrm{\: MHz}$. The high superconducting gap of niobium nitride can enable operation at elevated temperatures in future devices, and the fully planar geometry of the weak link eliminates superfluous material interfaces and capacitances. The investigation of small patches of material near the SIT can shed new light on the nature of the transition, including the role of dissipation and finite-size effects.

Related papers

• Native-oxide-passivated trilayer junctions for superconducting qubits [0.15710586783831507]
  fabrication methods based on subtractive patterning of superconductor--insulator--superconductor trilayers could provide the solution.<n>We design and fabricate transmon-like qubits and measure time-averaged coherence times up to 30 $mu$s at a qubit frequency of 5 GHz.
  arXiv  Detail & Related papers  (2025-04-04T14:39:45Z)
• Operation of a high-frequency, phase-slip qubit [0.0]
  We demonstrate the operation of a superconducting qubit based on a phase slip junction made using titanium nitride.<n>We perform readout and coherent control of the superconducting qubit, and measure qubit lifetimes.<n>Our results add the phase-slip junction as a tool for superconducting quantum information processing.
  arXiv  Detail & Related papers  (2025-02-10T21:22:24Z)
• Transport properties and quantum phase transitions in one-dimensional superconductor-ferromagnetic insulator heterostructures [44.99833362998488]
  We propose a one-dimensional electronic nanodevice inspired in recently fabricated semiconductor-superconductor-ferromagnetic insulator hybrids. We show that the device can be tuned across spin- and fermion parity-changing QPTs by adjusting the FMI layer length orange and/or by applying a global backgate voltage. Our findings suggest that these effects are experimentally accessible and offer a robust platform for studying quantum phase transitions in hybrid nanowires.
  arXiv  Detail & Related papers  (2024-10-18T22:25:50Z)
• Improved Coherence in Optically-Defined Niobium Trilayer Junction Qubits [45.786749852292246]
  Niobium offers the benefit of increased operating temperatures and frequencies for superconducting devices. We revisit niobium trilayer junctions and fabricate all-niobium transmons using only optical lithography. We characterize devices in the microwave domain, measuring coherence times up to $62mu$s and an average qubit quality factor above $105$.
  arXiv  Detail & Related papers  (2023-06-09T13:26:13Z)
• Silicide-based Josephson field effect transistors for superconducting qubits [0.0]
  An alternative "gatemon" qubit has recently appeared, which uses hybrid superconducting/semiconducting (S/Sm) devices as gate-tuned Josephson junctions. A scalable gatemon design could be made with CMOS Josephson Field-Effect Transistors as tunable weak link. A successful gate modulation of Andreev current in a silicon-based transistor represents a step towards fully CMOS-integrated superconducting quantum computers.
  arXiv  Detail & Related papers  (2022-09-06T18:00:03Z)
• Miniaturizing transmon qubits using van der Waals materials [2.86962140979607]
  Quantum computers can potentially achieve an exponential speedup versus classical computers on certain computational tasks. These qubits have large footprints due to their large capacitor electrodes needed to suppress losses. Here, we take advantage of the unique properties of the van der Waals (vdW) materials to reduce the qubit area.
  arXiv  Detail & Related papers  (2021-09-07T02:31:07Z)
• TOF-SIMS Analysis of Decoherence Sources in Nb Superconducting Resonators [48.7576911714538]
  Superconducting qubits have emerged as a potentially foundational platform technology. Material quality and interfacial structures continue to curb device performance. Two-level system defects in the thin film and adjacent regions introduce noise and dissipate electromagnetic energy.
  arXiv  Detail & Related papers  (2021-08-30T22:22:47Z)
• In-situ bandaged Josephson junctions for superconducting quantum processors [101.18253437732933]
  Shadow evaporation is commonly used to micro-fabricate the key element of superconducting qubits - the Josephson junction. Here, we present an improved shadow evaporation technique allowing one to fabricate sub-micrometer-sized Josephson junctions together with bandage layers in a single lithography step.
  arXiv  Detail & Related papers  (2021-01-05T11:08:09Z)
• Quantum Sensors for Microscopic Tunneling Systems [58.720142291102135]
  tunneling Two-Level-Systems (TLS) are important for micro-fabricated quantum devices such as superconducting qubits. We present a method to characterize individual TLS in virtually arbitrary materials deposited as thin-films. Our approach opens avenues for quantum material spectroscopy to investigate the structure of tunneling defects.
  arXiv  Detail & Related papers  (2020-11-29T09:57:50Z)
• Coherent superconducting qubits from a subtractive junction fabrication process [48.7576911714538]
  Josephson tunnel junctions are the centerpiece of almost any superconducting electronic circuit, including qubits. In recent years, sub-micron scale overlap junctions have started to attract attention. This work paves the way towards a more standardized process flow with advanced materials and growth processes, and constitutes an important step for large scale fabrication of superconducting quantum circuits.
  arXiv  Detail & Related papers  (2020-06-30T14:52:14Z)

This list is automatically generated from the titles and abstracts of the papers in this site.

This site does not guarantee the quality of this site (including all information) and is not responsible for any consequences.