Gate- and flux-tunable sin(2φ) Josephson element with planar-Ge junctions
Abstract Hybrid superconductor-semiconductor Josephson field-effect transistors (JoFETs) function as Josephson junctions with gate-tunable critical current. Additionally, they can feature a non-sinusoidal current-phase relation (CPR) containing multiple harmonics of the superconducting phase differe...
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| Format: | Article |
| Language: | English |
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Nature Portfolio
2025-01-01
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| Series: | Nature Communications |
| Online Access: | https://doi.org/10.1038/s41467-025-56245-7 |
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| author | Axel Leblanc Chotivut Tangchingchai Zahra Sadre Momtaz Elyjah Kiyooka Jean-Michel Hartmann Frédéric Gustavo Jean-Luc Thomassin Boris Brun Vivien Schmitt Simon Zihlmann Romain Maurand Étienne Dumur Silvano De Franceschi François Lefloch |
| author_facet | Axel Leblanc Chotivut Tangchingchai Zahra Sadre Momtaz Elyjah Kiyooka Jean-Michel Hartmann Frédéric Gustavo Jean-Luc Thomassin Boris Brun Vivien Schmitt Simon Zihlmann Romain Maurand Étienne Dumur Silvano De Franceschi François Lefloch |
| author_sort | Axel Leblanc |
| collection | DOAJ |
| description | Abstract Hybrid superconductor-semiconductor Josephson field-effect transistors (JoFETs) function as Josephson junctions with gate-tunable critical current. Additionally, they can feature a non-sinusoidal current-phase relation (CPR) containing multiple harmonics of the superconducting phase difference, a so-far underutilized property. Here we exploit this multi-harmonicity to create a Josephson circuit element with an almost perfectly π-periodic CPR, indicative of a largely dominant charge-4e supercurrent transport. We realize such a Josephson element, recently proposed as building block of a protected superconducting qubit, using a superconducting quantum interference device (SQUID) with low-inductance aluminum arms and two nominally identical JoFETs. The latter are fabricated from a SiGe/Ge/SiGe quantum-well heterostructure embedding a high-mobility two-dimensional hole gas. By carefully adjusting the JoFET gate voltages and finely tuning the magnetic flux through the SQUID close to half a flux quantum, we achieve a regime where the $$\sin (2\varphi )$$ sin ( 2 φ ) component accounts for more than 95% of the total supercurrent. This result demonstrates a new promising route towards parity-protected superconducting qubits. |
| format | Article |
| id | doaj-art-dddac8d9066a4268bb34bcba76f10838 |
| institution | Kabale University |
| issn | 2041-1723 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | Nature Portfolio |
| record_format | Article |
| series | Nature Communications |
| spelling | doaj-art-dddac8d9066a4268bb34bcba76f108382025-01-26T12:42:48ZengNature PortfolioNature Communications2041-17232025-01-011611710.1038/s41467-025-56245-7Gate- and flux-tunable sin(2φ) Josephson element with planar-Ge junctionsAxel Leblanc0Chotivut Tangchingchai1Zahra Sadre Momtaz2Elyjah Kiyooka3Jean-Michel Hartmann4Frédéric Gustavo5Jean-Luc Thomassin6Boris Brun7Vivien Schmitt8Simon Zihlmann9Romain Maurand10Étienne Dumur11Silvano De Franceschi12François Lefloch13Univ. Grenoble AlpesUniv. Grenoble AlpesInstitut NéelUniv. Grenoble AlpesUniv. Grenoble AlpesUniv. Grenoble AlpesUniv. Grenoble AlpesUniv. Grenoble AlpesUniv. Grenoble AlpesUniv. Grenoble AlpesUniv. Grenoble AlpesUniv. Grenoble AlpesUniv. Grenoble AlpesUniv. Grenoble AlpesAbstract Hybrid superconductor-semiconductor Josephson field-effect transistors (JoFETs) function as Josephson junctions with gate-tunable critical current. Additionally, they can feature a non-sinusoidal current-phase relation (CPR) containing multiple harmonics of the superconducting phase difference, a so-far underutilized property. Here we exploit this multi-harmonicity to create a Josephson circuit element with an almost perfectly π-periodic CPR, indicative of a largely dominant charge-4e supercurrent transport. We realize such a Josephson element, recently proposed as building block of a protected superconducting qubit, using a superconducting quantum interference device (SQUID) with low-inductance aluminum arms and two nominally identical JoFETs. The latter are fabricated from a SiGe/Ge/SiGe quantum-well heterostructure embedding a high-mobility two-dimensional hole gas. By carefully adjusting the JoFET gate voltages and finely tuning the magnetic flux through the SQUID close to half a flux quantum, we achieve a regime where the $$\sin (2\varphi )$$ sin ( 2 φ ) component accounts for more than 95% of the total supercurrent. This result demonstrates a new promising route towards parity-protected superconducting qubits.https://doi.org/10.1038/s41467-025-56245-7 |
| spellingShingle | Axel Leblanc Chotivut Tangchingchai Zahra Sadre Momtaz Elyjah Kiyooka Jean-Michel Hartmann Frédéric Gustavo Jean-Luc Thomassin Boris Brun Vivien Schmitt Simon Zihlmann Romain Maurand Étienne Dumur Silvano De Franceschi François Lefloch Gate- and flux-tunable sin(2φ) Josephson element with planar-Ge junctions Nature Communications |
| title | Gate- and flux-tunable sin(2φ) Josephson element with planar-Ge junctions |
| title_full | Gate- and flux-tunable sin(2φ) Josephson element with planar-Ge junctions |
| title_fullStr | Gate- and flux-tunable sin(2φ) Josephson element with planar-Ge junctions |
| title_full_unstemmed | Gate- and flux-tunable sin(2φ) Josephson element with planar-Ge junctions |
| title_short | Gate- and flux-tunable sin(2φ) Josephson element with planar-Ge junctions |
| title_sort | gate and flux tunable sin 2φ josephson element with planar ge junctions |
| url | https://doi.org/10.1038/s41467-025-56245-7 |
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