Kiyooka Elyjah, Tangchingchai Chotivut, Noirot Leo, Leblanc Axel, Brun Boris, Zihlmann Simon, Maurand Romain, Schmitt Vivien, Dumur Étienne, Hartmann Jean-Michel, Lefloch Francois, De Franceschi Silvano
Université Grenoble Alpes,CEA, Grenoble INP, IRIG, PHELIQS, 38000 Grenoble, France.
Université Grenoble Alpes,CEA, LETI, 38000 Grenoble, France.
Nano Lett. 2025 Jan 8;25(1):562-568. doi: 10.1021/acs.nanolett.4c05539. Epub 2024 Dec 17.
Gatemons are superconducting qubits resembling transmons, with a gate-tunable semiconducting weak link as the Josephson element. Here, we report a gatemon device featuring an aluminum microwave circuit on a Ge/SiGe heterostructure embedding a Ge quantum well. Owing to the superconducting proximity effect, the high-mobility two-dimensional hole gas confined in this well provides a gate-tunable superconducting weak link between two Al contacts. We perform Rabi oscillation and Ramsey interference measurements, demonstrate the gate-voltage dependence of the qubit frequency, and measure the qubit anharmonicity. We find relaxation times up to 119 ns, and Ramsey coherence times up to 70 ns, and a qubit frequency gate-tunable over 3.5 GHz. The reported proof-of-concept reproduces the results of a very recent work [Sagi et al. 2024, 15, 6400] using similar Ge/SiGe heterostructures, thereby validating a novel platform for the development of gatemons and parity-protected cos(2ϕ) qubits.
门控量子比特是类似于穿通量子比特的超导量子比特，其约瑟夫森元件为栅极可调谐半导体弱连接。在此，我们报道了一种门控量子比特器件，它在嵌入锗量子阱的锗/硅锗异质结构上采用了铝微波电路。由于超导邻近效应，限制在该量子阱中的高迁移率二维空穴气在两个铝接触之间提供了一个栅极可调谐超导弱连接。我们进行了拉比振荡和拉姆齐干涉测量，证明了量子比特频率对栅极电压的依赖性，并测量了量子比特非谐性。我们发现弛豫时间长达119纳秒，拉姆齐相干时间长达70纳秒，并且量子比特频率在3.5吉赫兹范围内可通过栅极调节。所报道的概念验证重现了最近一项使用类似锗/硅锗异质结构的工作 [萨吉等人，《科学》2024年，15卷，6400页] 的结果，从而验证了一个用于开发门控量子比特和奇偶保护cos(2ϕ) 量子比特的新型平台。
