High-performance transmon qubits with an epitaxially grown TiN film on Si (100) substrate

ORAL

Abstract

The transmon qubit is a fundamental superconducting quantum element, and its performance directly affects the performance of integrated quantum circuits. The energy decay time of a transmon is known to be sensitive to the surface condition of the superconducting electrodes, and there have been many attempts to improve the performance of transmons by changing the materials and surface treatments. Here we present the properties of our transmons consisting of a shadow-evaporated Al Josephson junction and TiN electrodes grown on Si (100) substrate with domain-matching epitaxy at high temperature. The energy decay time of 250 μs is obtained for a transmon with the transition frequency of 4.5 GHz. We evaluate the loss mechanism of our transmons by changing their designs.

*This work was supported by the Japan Science and Technology Agency (Moonshot R&D, JPMJMS2067), MEXT Q-LEAP (Grant No. JPMXS0118068682), JSPS KAKENHI (Grant No. JP22J15257), and the Inamori Research Institute for Science (InaRIS) Fellowship Program.

–

Presenters

  • Atsushi Noguchi

    • The University of Tokyo, Japan
    • Komaba Institute for Science, The University of Tokyo
    • KIS, The Univ. of Tokyo

Authors

  • Atsushi Noguchi

    • The University of Tokyo, Japan
    • Komaba Institute for Science, The University of Tokyo
    • KIS, The Univ. of Tokyo

  • Shotaro Shirai

    • Komaba Institute for Science, The University of Tokyo
    • KIS, The Univ. of Tokyo

  • Shuhei Tamate

    • RIKEN
    • RIKEN Center for Quantum Computing

  • Alexander Badrutdinov

    • RIKEN Center for Quantum Computing

  • Shion Chen

    • International Center for Elementary Particle Physics, The University of Tokyo

  • Toshiaki Inada

    • International Center for Elementary Particle Physics, The University of Tokyo

  • Tatsumi Nitta

    • International Center for Elementary Particle Physics, The University of Tokyo

  • Shoji Asai

    • International Center for Elementary Particle Physics, The University of Tokyo

  • Yuji Hishida

    • National Institute of Information and Communications Technology

  • Hirotaka Terai

    • National Institute of Information and Communications Technology, Japan
    • National Institute of Information and Communications Technology

  • Yasunobu Nakamura

    • RIKEN Center for Quantum Computing
    • RQC, RIKEN