@article{d2ae90d5da16460fb2656389c47a0a9e,
title = "Integration of Topological Insulator Josephson Junctions in Superconducting Qubit Circuits",
abstract = "The integration of semiconductor Josephson junctions (JJs) in superconducting quantum circuits provides a versatile platform for hybrid qubits and offers a powerful way to probe exotic quasiparticle excitations. Recent proposals for using circuit quantum electrodynamics (cQED) to detect topological superconductivity motivate the integration of novel topological materials in such circuits. Here, we report on the realization of superconducting transmon qubits implemented with (Bi0.06Sb0.94)2Te3topological insulator (TI) JJs using ultrahigh vacuum fabrication techniques. Microwave losses on our substrates, which host monolithically integrated hardmasks used for the selective area growth of TI nanostructures, imply microsecond limits to relaxation times and, thus, their compatibility with strong-coupling cQED. We use the cavity-qubit interaction to show that the Josephson energy of TI-based transmons scales with their JJ dimensions and demonstrate qubit control as well as temporal quantum coherence. Our results pave the way for advanced investigations of topological materials in both novel Josephson and topological qubits.",
keywords = "Josephson junctions, selective area growth, stencil lithography, superconducting qubits, topological insulators, 22/4 OA procedure",
author = "Schmitt, {Tobias W.} and Connolly, {Malcolm R.} and Michael Schleenvoigt and Chenlu Liu and Oscar Kennedy and Ch{\'a}vez-Garcia, {Jos{\'e} M.} and Jalil, {Abdur R.} and Benjamin Bennemann and Stefan Trellenkamp and Florian Lentz and Elmar Neumann and Tobias Lindstr{\"o}m and {De Graaf}, {Sebastian E.} and Erwin Berenschot and Niels Tas and Gregor Mussler and Petersson, {Karl D.} and Detlev Gr{\"u}tzmacher and Peter Sch{\"u}ffelgen",
note = "Funding Information: We gratefully acknowledge helpful discussions with J. Burnett, M. Kjaergaard, and Th. Sch{\"a}pers. We thank A. Hertel and M. Eichinger for their assistance with the time-domain measurements. T.W.S. thanks C. M. Marcus for supporting a stay at the Center for Quantum Devices. This work was supported financially by the German Federal Ministry of Education and Research (BMBF) via the Quantum Futur project “MajoranaChips” (Grant No. 13N15264) within the funding program Photonic Research Germany, the Priority Program SPP1666, European Union{\textquoteright}s Horizon 2020 research and innovation program (grant agreement No 766714/HiTIMe), the UK department for Business Energy and Industrial Strategy (BEIS) through the UK national quantum technologies programme, Germany{\textquoteright}s Excellence Strategy - Cluster of Excellence “Matter and Light for Quantum Computing” (ML4Q) EXC 2004/1-390534769, as well as the Bavarian Ministry of Economic Affairs, Regional Development and Energy within Bavaria{\textquoteright}s High-Tech Agenda Project “Bausteine f{\"u}r das Quantencomputing auf Basis topologischer Materialien mit experimentellen und theoretischen Ans{\"a}tzen“ (grant allocation no. 07 02/686 58/1/21 1/22 2/23). We moreover acknowledge support by the IVF project “Scalable Solid State Quantum Computing”. M.R.C. received funding from the European Union{\textquoteright}s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No. 750777 and EPSRC (EP/L020963/1). T.W.S. acknowledges support from the German Academic Exchange Service (DAAD). K.D.P. and J.M.C.G. acknowledge support from Microsoft and the Danish National Research Foundation. Publisher Copyright: {\textcopyright} 2022 American Chemical Society. All rights reserved.",
year = "2022",
month = apr,
day = "13",
doi = "10.1021/acs.nanolett.1c04055",
language = "English",
volume = "22",
pages = "2595--2602",
journal = "Nano letters",
issn = "1530-6984",
publisher = "American Chemical Society",
number = "7",
}