Tuning Supercurrent in Josephson Field-Effect Transistors Using h-BN Dielectric

Barati, Fatemeh; Thompson, Josh P.; Dartiailh, Matthieu; Sardashti, Kasra; Mayer, William; Yuan, Joseph; Wickramasinghe, Kaushini; Watanabe, Kenji; Taniguchi, Takashi; Churchill, Hugh; Shabani, Javad

doi:10.1021/acs.nanolett.0c03183

Cited by 17 publications

(7 citation statements)

References 36 publications

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“…Experimental feasibility of the proposed mini-gate controlled MBS fusion builds on the demonstrated topological superconductivity in epitaxial InAs/Al planar JJs 31 , 42 . This is further corroborated by using the same platform to demonstrate that mini gates can modulate the superconducting state in our fabricated SJ, shown with scanning electron microscope (SEM) images in Fig.…”

Section: Resultsmentioning

confidence: 96%

Fusion of Majorana bound states with mini-gate control in two-dimensional systems

et al. 2022

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A hallmark of topological superconductivity is the non-Abelian statistics of Majorana bound states (MBS), its chargeless zero-energy emergent quasiparticles. The resulting fractionalization of a single electron, stored nonlocally as a two spatially-separated MBS, provides a powerful platform for implementing fault-tolerant topological quantum computing. However, despite intensive efforts, experimental support for MBS remains indirect and does not probe their non-Abelian statistics. Here we propose how to overcome this obstacle in mini-gate controlled planar Josephson junctions (JJs) and demonstrate non-Abelian statistics through MBS fusion, detected by charge sensing using a quantum point contact, based on dynamical simulations. The feasibility of preparing, manipulating, and fusing MBS in two-dimensional (2D) systems is supported in our experiments which demonstrate the gate control of topological transition and superconducting properties with five mini gates in InAs/Al-based JJs. While we focus on this well-established platform, where the topological superconductivity was already experimentally detected, our proposal to identify elusive non-Abelian statistics motivates also further MBS studies in other gate-controlled 2D systems.

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Section: Resultsmentioning

confidence: 96%

Fusion of Majorana bound states with mini-gate control in two-dimensional systems

et al. 2022

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“…As an SiO x or AlO x gate dielectric could introduce a higher density of charge traps and interface states [61], it may be more favorable to use monolayer thick h-BN as a gate dielectric, which has low density of charge traps, and low microwave absorption, possibly leading to better device performance while maintaining supercurrent tunability [62].…”

Section: Discussionmentioning

confidence: 99%

Epitaxial superconductor-semiconductor two-dimensional systems for superconducting quantum circuits

Yuan

Wickramasinghe

Strickland

et al. 2021

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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Qubits on solid state devices could potentially provide the rapid control necessary for developing scalable quantum information processors. Materials innovation and design breakthroughs have increased functionality and coherence of qubits substantially over the past two decades. Here, we show by improving interface between InAs as a semiconductor and Al as a superconductor, one can reliably fabricate voltage-controlled Josephson junction field effect transistor (JJ-FET) that can be used as tunable qubits, resonators, and coupler switches. We find that bandgap engineering is crucial in realizing a two-dimensional electron gas near the surface. In addition, we show how the coupling between the semiconductor layer and the superconducting contacts can affect qubit properties. We present the anharmonicity and coupling strengths from one and two-photon absorption in a quantum two level system fabricated with a JJ-FET.

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“…We develop a top gate structure by using h-BN as the dielectric layer to minimize the distance between the gate and the superconductor, which enables the investigation of the gating effect in metallic superconductors on several nanometer scales of gating distance. BN crystal possesses desirable properties for our vertical devices, such as a high-quality insulator with a large bandgap, low dielectric constant, and precise control over thickness at the atomic layer level [36,37]. Thus, it is an ideal choice for serving as the insulating layer in our devices.…”

Section: Sample Fabrication and Measurement Techniquesmentioning

confidence: 99%

High-energy electron local injection in top-gated metallic superconductor switch

Wei

et al. 2023

Supercond. Sci. Technol.

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The gate-tunable superconductivity in metallic superconductors has recently attracted significant attention due to its rich physics and potential applications in next-generation superconducting electronics. Although the operating principles of these devices have been attributed to the small leakage currents of high-energy electrons in recent experiments, the generated phonons can spread over considerable distances in the substrate, which may limit their further applications. Here, we utilize a top gate structure with monocrystalline h-BN as a gate dielectric and demonstrate the gate-adjustable supercurrent in a metallic Nb microbridge. The gate current of the devices perfectly follows the Fowler-Nordheim law of field emission, indicating that the injection of high-energy electrons presumably causes the suppression of the supercurrent. Our devices reduce the distance between the gate and the microbridge to a few nanometers or less, significantly minimizing the generated phonons’ spreading distance and power dissipation in the substrate or surrounding environment. These observations demonstrate that top-gated metallic superconducting switches with local electron injection can improve the device integration density, providing us with more versatile and practical opportunities to explore superconducting circuit architecture.

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Tuning Supercurrent in Josephson Field-Effect Transistors Using h-BN Dielectric

Cited by 17 publications

References 36 publications

Fusion of Majorana bound states with mini-gate control in two-dimensional systems

Fusion of Majorana bound states with mini-gate control in two-dimensional systems

Epitaxial superconductor-semiconductor two-dimensional systems for superconducting quantum circuits

High-energy electron local injection in top-gated metallic superconductor switch

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