One of the consequences of Cooper pairs having a finite momentum in the interlayer of a Josephson junction is π-junction behavior. The finite momentum can either be due to an exchange field in ferromagnetic Josephson junctions, or due to the Zeeman effect. Here, we report the observation of Zeeman-effect-induced 0-π transitions in Bi_{1-x}Sb_{x}, three-dimensional Dirac semimetal-based Josephson junctions. The large in-plane g factor allows tuning of the Josephson junctions from 0 to π regimes. This is revealed by measuring a π phase shift in the current-phase relation measured with an asymmetric superconducting quantum interference device (SQUID). Additionally, we directly measure a nonsinusoidal current-phase relation in the asymmetric SQUID, consistent with models for ballistic Josephson transport.
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http://dx.doi.org/10.1103/PhysRevLett.123.026802 | DOI Listing |
Adv Mater
January 2025
Oxford Quantum Circuits, Thames Valley Science Park, Shinfield, Reading, RG2 9LH, UK.
A sapphire machining process integrated with intermediate-scale quantum processors is demonstrated. The process allows through-substrate electrical connections, necessary for low-frequency mode-mitigation, as well as signal-routing, which are vital as quantum computers scale in qubit number, and thus dimension. High-coherence qubits are required to build fault-tolerant quantum computers and so material choices are an important consideration when developing a qubit technology platform.
View Article and Find Full Text PDFACS Nano
January 2025
Peter Grünberg Institut (PGI-9), Forschungszentrum Jülich, 52425 Jülich, Germany.
The combination of an ordinary s-type superconductor with three-dimensional topological insulators creates a promising platform for fault-tolerant topological quantum computing circuits based on Majorana braiding. The backbone of the braiding mechanism are three-terminal Josephson junctions. It is crucial to understand the transport in these devices for further use in quantum computing applications.
View Article and Find Full Text PDFNat Commun
January 2025
NanoLund and Solid State Physics, Lund University, Box 118, 22100, Lund, Sweden.
Nonlinear effects play a central role in photonics as they form the foundation for most of the device functionalities such as amplification and quantum state preparation and detection. Typically the nonlinear effects are weak and emerge only at high photon numbers with strong drive. Here we present an experimental study of a Josephson junction -based high-impedance resonator.
View Article and Find Full Text PDFNat Commun
January 2025
CNR Nanotec, Institute of Nanotechnology, via Monteroni, 73100, Lecce, Italy.
Macroscopic coherence in quantum fluids allows the observation of interference effects in their wavefunctions, and enables applications such as superconducting quantum interference devices based on Josephson tunneling. The Josephson effect manifests in both fermionic and bosonic systems, and has been well studied in superfluid helium and atomic Bose-Einstein condensates. In exciton-polariton condensates-that offer a path to integrated semiconductor platforms-creating weak links in ring geometries has so far remained challenging.
View Article and Find Full Text PDFJ Phys Condens Matter
January 2025
School of Physics, University of Hyderabad, Prof. C. R. Rao Road, Gachibowli, Hyderabad 500046, India.
The Josephson diode effect (JDE), characterized by asymmetric critical currents in a Josephson junction, has drawn considerable attention in the field of condensed matter physics. We investigate the conditions under which JDE can manifest in a one-dimensional Josephson junction composed of a spin-orbit-coupled quantum wire with an applied Zeeman field, connected between two superconductors (SCs). Our study reveals that while spin-orbit coupling (SOC) and a Zeeman field in the quantum wire are not sufficient to induce JDE when the SCs are purely singlet, introduction of triplet pairing in the SCs leads to the emergence of JDE.
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