RQC Seminar

8th RQC Seminar

• Speaker

  Dr. Sunmi Kim (National Institute of Information and Communications Technology（NICT））

• Date

  16:00-17:00 (JST), March 9, 2022 (Wednesday)

• Venue

  Online

• Title

  Superconducting qubits with nitride Josephson junctions

• Inquiries

  Superconducting Quantum Electronics Joint Research Unit, RQC

Abstract
In this talk, I introduce our recent works on the development of all-nitride superconducting qubit on silicon substrate [1]. We have fabricated an all-nitride capacitively-shunted flux qubit coupled to a half-wavelength coplanar waveguide resonator by utilizing the growth technique of a full-epitaxial NbN/AlN/NbN tri-layer. Also, by employing a Si substrate instead of a conventional MgO substrate for epitaxial growth of NbN film, this nitride flux qubit has demonstrated a significant improvement in coherence times, such as T1 = 16.3 μs and T2 = 21.5 μs, which are more than an order of magnitude longer than those reported in the literature using MgO substrates [2]. These results are an important step towards constructing a new platform for superconducting quantum hardware.
[1] S. Kim et al., Communications Materials 2, 98 (2021).
[2] Y. Nakamura et al., Appl. Phys. Lett. 99, 212502 (2011).

Flyer: 8th RQC Seminar Flyer