In this Letter we study the effect of time-reversal symmetric impurities on the Josephson supercurrent through two-dimensional helical metals such as on a topological insulator surface state. We show that, contrary to the usual superconducting-normal metal-superconducting junctions, the suppression of the supercurrent in the superconducting-helical metal-superconducting junction is mainly due to fluctuations of impurities in the junctions. Our results, which are a condensed matter realization of a part of the Mikheyev-Smirnov-Wolfenstein effect for neutrinos, show that the relationship between normal state conductance and the critical current of Josephson junctions is significantly modified for Josephson junctions on the surface of topological insulators. We also study the temperature dependence of the supercurrent and present a two fluid model which can explain some of the recent experimental results in Josephson junctions on the edge of topological insulators.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1103/PhysRevLett.116.037001 | DOI Listing |
Materials (Basel)
January 2025
CNR-IOM-Istituto Officina dei Materiali, Consiglio Nazionale delle Ricerche, 34149 Trieste, Italy.
Hybrid systems consisting of highly transparent channels of low-dimensional semiconductors between superconducting elements allow the formation of quantum electronic circuits. Therefore, they are among the novel material platforms that could pave the way for scalable quantum computation. To this aim, InAs two-dimensional electron gases are among the ideal semiconductor systems due to their vanishing Schottky barrier; however, their exploitation is limited by the unavailability of commercial lattice-matched substrates.
View Article and Find Full Text PDFNat Commun
January 2025
Univ. Grenoble Alpes, CEA, Grenoble INP, IRIG-PHELIQS, 38000, Grenoble, France.
Hybrid superconductor-semiconductor Josephson field-effect transistors (JoFETs) function as Josephson junctions with gate-tunable critical current. Additionally, they can feature a non-sinusoidal current-phase relation (CPR) containing multiple harmonics of the superconducting phase difference, a so-far underutilized property. Here we exploit this multi-harmonicity to create a Josephson circuit element with an almost perfectly π-periodic CPR, indicative of a largely dominant charge-4e supercurrent transport.
View Article and Find Full Text PDFAdv 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 PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!