Hexagonal boron nitride as a low-loss dielectric for superconducting quantum circuits and qubits

Joel I-J Wang; Megan A Yamoah; Qing Li; Amir H Karamlou; Thao Dinh; Bharath Kannan; Jochen Braumüller; David Kim; Alexander J Melville; Sarah E Muschinske; Bethany M Niedzielski; Kyle Serniak; Youngkyu Sung; Roni Winik; Jonilyn L Yoder; Mollie E Schwartz; Kenji Watanabe; Takashi Taniguchi; Terry P Orlando; Simon Gustavsson; Pablo Jarillo-Herrero; William D Oliver

doi:10.1038/s41563-021-01187-w

Hexagonal boron nitride as a low-loss dielectric for superconducting quantum circuits and qubits

Nat Mater. 2022 Apr;21(4):398-403. doi: 10.1038/s41563-021-01187-w. Epub 2022 Jan 27.

Authors

Joel I-J Wang^#¹, Megan A Yamoah^#^{2

3}, Qing Li³, Amir H Karamlou^{4

3}, Thao Dinh², Bharath Kannan^{4

3}, Jochen Braumüller⁴, David Kim⁵, Alexander J Melville⁵, Sarah E Muschinske³, Bethany M Niedzielski⁵, Kyle Serniak⁵, Youngkyu Sung^{4

3}, Roni Winik⁴, Jonilyn L Yoder⁵, Mollie E Schwartz⁵, Kenji Watanabe⁶, Takashi Taniguchi⁷, Terry P Orlando³, Simon Gustavsson⁴, Pablo Jarillo-Herrero⁸, William D Oliver^{9

10

11

12}

Affiliations

¹ Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA. [email protected].
² Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA.
³ Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA.
⁴ Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA.
⁵ MIT Lincoln Laboratory, Lexington, MA, USA.
⁶ Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Japan.
⁷ International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Japan.
⁸ Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA. [email protected].
⁹ Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA. [email protected].
¹⁰ Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA. [email protected].
¹¹ Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA. [email protected].
¹² MIT Lincoln Laboratory, Lexington, MA, USA. [email protected].

^# Contributed equally.

PMID: 35087240
DOI: 10.1038/s41563-021-01187-w

Abstract

Dielectrics with low loss at microwave frequencies are imperative for high-coherence solid-state quantum computing platforms. Here we study the dielectric loss of hexagonal boron nitride (hBN) thin films in the microwave regime by measuring the quality factor of parallel-plate capacitors (PPCs) made of NbSe₂-hBN-NbSe₂ heterostructures integrated into superconducting circuits. The extracted microwave loss tangent of hBN is bounded to be at most in the mid-10^-6 range in the low-temperature, single-photon regime. We integrate hBN PPCs with aluminium Josephson junctions to realize transmon qubits with coherence times reaching 25 μs, consistent with the hBN loss tangent inferred from resonator measurements. The hBN PPC reduces the qubit feature size by approximately two orders of magnitude compared with conventional all-aluminium coplanar transmons. Our results establish hBN as a promising dielectric for building high-coherence quantum circuits with substantially reduced footprint and with a high energy participation that helps to reduce unwanted qubit cross-talk.

Abstract

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