--- APC_amount: '12345' _id: '14793' abstract: - lang: eng text: Superconductor/semiconductor hybrid devices have attracted increasing interest in the past years. Superconducting electronics aims to complement semiconductor technology, while hybrid architectures are at the forefront of new ideas such as topological superconductivity and protected qubits. In this work, we engineer the induced superconductivity in two-dimensional germanium hole gas by varying the distance between the quantum well and the aluminum. We demonstrate a hard superconducting gap and realize an electrically and flux tunable superconducting diode using a superconducting quantum interference device (SQUID). This allows to tune the current phase relation (CPR), to a regime where single Cooper pair tunneling is suppressed, creating a sin(2y) CPR. Shapiro experiments complement this interpretation and the microwave drive allows to create a diode with ≈ 100% efficiency. The reported results open up the path towards integration of spin qubit devices, microwave resonators and (protected) superconducting qubits on the same silicon technology compatible platform. acknowledged_ssus: - _id: M-Shop - _id: NanoFab acknowledgement: "We acknowledge Alexander Brinkmann, Alessandro Crippa, Francesco Giazotto, Andrew Higginbotham, Andrea Iorio, Giordano Scappucci, Christian Schonenberger, and Lukas Splitthoff for helpful discussions. We thank Marcel Verheijen for the support in the TEM analysis. This research and related results were made possible with the support of the NOMIS\r\nFoundation. It was supported by the Scientific Service Units of ISTA through resources provided by the MIBA Machine Shop and the nanofabrication facility, the European Union’s Horizon 2020 research andinnovation programme under Grant Agreement No 862046, the HORIZONRIA\r\n101069515 project, the European Innovation Council Pathfinder grant no. 101115315 (QuKiT), and the FWF Projects #P-32235, #P-36507 and #F-8606. For the purpose of open access, the authors have applied a CC BY public copyright licence to any Author Accepted Manuscript version arising from this submission. R.S.S. acknowledges Spanish CM “Talento Program\"\r\nProject No. 2022-T1/IND-24070. J.J. acknowledges European Research Council TOCINA 834290." article_number: '169' article_processing_charge: Yes article_type: original author: - first_name: Marco full_name: Valentini, Marco id: C0BB2FAC-D767-11E9-B658-BC13E6697425 last_name: Valentini - first_name: Oliver full_name: Sagi, Oliver id: 71616374-A8E9-11E9-A7CA-09ECE5697425 last_name: Sagi - first_name: Levon full_name: Baghumyan, Levon id: 7aa1f788-b527-11ee-aa9e-e6111a79e0c7 last_name: Baghumyan - first_name: Thijs full_name: de Gijsel, Thijs id: a0ece13c-b527-11ee-929d-bad130106eee last_name: de Gijsel - first_name: Jason full_name: Jung, Jason id: 4C9ACE7A-F248-11E8-B48F-1D18A9856A87 last_name: Jung - first_name: Stefano full_name: Calcaterra, Stefano last_name: Calcaterra - first_name: Andrea full_name: Ballabio, Andrea last_name: Ballabio - first_name: Juan L full_name: Aguilera Servin, Juan L id: 2A67C376-F248-11E8-B48F-1D18A9856A87 last_name: Aguilera Servin orcid: 0000-0002-2862-8372 - first_name: Kushagra full_name: Aggarwal, Kushagra id: b22ab905-3539-11eb-84c3-fc159dcd79cb last_name: Aggarwal orcid: 0000-0001-9985-9293 - first_name: Marian full_name: Janik, Marian id: 396A1950-F248-11E8-B48F-1D18A9856A87 last_name: Janik - first_name: Thomas full_name: Adletzberger, Thomas id: 38756BB2-F248-11E8-B48F-1D18A9856A87 last_name: Adletzberger - first_name: Rubén full_name: Seoane Souto, Rubén last_name: Seoane Souto - first_name: Martin full_name: Leijnse, Martin last_name: Leijnse - first_name: Jeroen full_name: Danon, Jeroen last_name: Danon - first_name: Constantin full_name: Schrade, Constantin last_name: Schrade - first_name: Erik full_name: Bakkers, Erik last_name: Bakkers - first_name: Daniel full_name: Chrastina, Daniel last_name: Chrastina - first_name: Giovanni full_name: Isella, Giovanni last_name: Isella - first_name: Georgios full_name: Katsaros, Georgios id: 38DB5788-F248-11E8-B48F-1D18A9856A87 last_name: Katsaros orcid: 0000-0001-8342-202X citation: ama: Valentini M, Sagi O, Baghumyan L, et al. Parity-conserving Cooper-pair transport and ideal superconducting diode in planar germanium. Nature Communications. 2024;15. doi:10.1038/s41467-023-44114-0 apa: Valentini, M., Sagi, O., Baghumyan, L., de Gijsel, T., Jung, J., Calcaterra, S., … Katsaros, G. (2024). Parity-conserving Cooper-pair transport and ideal superconducting diode in planar germanium. Nature Communications. Springer Nature. https://doi.org/10.1038/s41467-023-44114-0 chicago: Valentini, Marco, Oliver Sagi, Levon Baghumyan, Thijs de Gijsel, Jason Jung, Stefano Calcaterra, Andrea Ballabio, et al. “Parity-Conserving Cooper-Pair Transport and Ideal Superconducting Diode in Planar Germanium.” Nature Communications. Springer Nature, 2024. https://doi.org/10.1038/s41467-023-44114-0. ieee: M. Valentini et al., “Parity-conserving Cooper-pair transport and ideal superconducting diode in planar germanium,” Nature Communications, vol. 15. Springer Nature, 2024. ista: Valentini M, Sagi O, Baghumyan L, de Gijsel T, Jung J, Calcaterra S, Ballabio A, Aguilera Servin JL, Aggarwal K, Janik M, Adletzberger T, Seoane Souto R, Leijnse M, Danon J, Schrade C, Bakkers E, Chrastina D, Isella G, Katsaros G. 2024. Parity-conserving Cooper-pair transport and ideal superconducting diode in planar germanium. Nature Communications. 15, 169. mla: Valentini, Marco, et al. “Parity-Conserving Cooper-Pair Transport and Ideal Superconducting Diode in Planar Germanium.” Nature Communications, vol. 15, 169, Springer Nature, 2024, doi:10.1038/s41467-023-44114-0. short: M. Valentini, O. Sagi, L. Baghumyan, T. de Gijsel, J. Jung, S. Calcaterra, A. Ballabio, J.L. Aguilera Servin, K. Aggarwal, M. Janik, T. Adletzberger, R. Seoane Souto, M. Leijnse, J. Danon, C. Schrade, E. Bakkers, D. Chrastina, G. Isella, G. Katsaros, Nature Communications 15 (2024). dataavailabilitystatement: All experimental data included in this work are available at https://zenodo.org/records/10119346. date_created: 2024-01-14T23:00:56Z date_published: 2024-01-02T00:00:00Z date_updated: 2026-02-26T11:39:00Z day: '02' ddc: - '530' department: - _id: GeKa doi: 10.1038/s41467-023-44114-0 ec_funded: 1 external_id: oaworkID: - w4390499170 pmid: - '38167818' file: - access_level: open_access checksum: ef79173b45eeaf984ffa61ef2f8a52ab content_type: application/pdf creator: dernst date_created: 2024-01-17T11:03:00Z date_updated: 2024-01-17T11:03:00Z file_id: '14825' file_name: 2024_NatureComm_Valentini.pdf file_size: 2336595 relation: main_file success: 1 file_date_updated: 2024-01-17T11:03:00Z has_accepted_license: '1' intvolume: ' 15' language: - iso: eng month: '01' oa: 1 oa_version: Published Version oaworkID: 1 pmid: 1 project: - _id: 237E5020-32DE-11EA-91FC-C7463DDC885E call_identifier: H2020 grant_number: '862046' name: TOPOLOGICALLY PROTECTED AND SCALABLE QUANTUM BITS - _id: 34c0acea-11ca-11ed-8bc3-8775e10fd452 grant_number: '101069515' name: Integrated GermaNIum quanTum tEchnology - _id: bdc2ca30-d553-11ed-ba76-cf164a5bb811 grant_number: '101115315' name: Quantum bits with Kitaev Transmons - _id: 237B3DA4-32DE-11EA-91FC-C7463DDC885E call_identifier: FWF grant_number: P32235 name: Towards scalable hut wire quantum devices - _id: bd8bd29e-d553-11ed-ba76-f0070d4b237a grant_number: P36507 name: Merging spin and superconducting qubits in planar Ge - _id: 34a66131-11ca-11ed-8bc3-a31681c6b03e grant_number: F8606 name: Conventional and unconventional topological superconductors publication: Nature Communications publication_identifier: eissn: - 2041-1723 publication_status: published publisher: Springer Nature quality_controlled: '1' researchdata_availability: yes scopus_import: '1' status: public supplementarymaterial: yes title: Parity-conserving Cooper-pair transport and ideal superconducting diode in planar germanium tmp: image: /images/cc_by.png legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0) short: CC BY (4.0) type: journal_article user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 volume: 15 year: '2024' ... --- _id: '13286' abstract: - lang: eng text: Semiconductor-superconductor hybrid systems are the harbour of many intriguing mesoscopic phenomena. This material combination leads to spatial variations of the superconducting properties, which gives rise to Andreev bound states (ABSs). Some of these states might exhibit remarkable properties that render them highly desirable for topological quantum computing. The most prominent and hunted of such states are Majorana zero modes (MZMs), quasiparticles equals to their own quasiparticles that they follow non-abelian statistics. In this thesis, we first introduce the general framework of such hybrid systems and, then, we unveil a series of mesoscopic phenomena that we discovered. Firstly, we show tunneling spectroscopy experiments on full-shell nanowires (NWs) showing that unwanted quantum-dot states coupled to superconductors (Yu-Shiba-Rusinov states) can mimic MZMs signatures. Then, we introduce a novel protocol which allowed the integration of tunneling spectroscopy with Coulomb spectroscopy within the same device. Employing this approach on both full-shell NWs and partial-shell NWs, we demonstrated that longitudinally confined states reveal charge transport phenomenology similar to the one expected for MZMs. These findings shed light on the intricate interplay between superconductivity and quantum confinement, which brought us to explore another material platform, i.e. a two-dimensional Germanium hole gas. After developing a robust way to induce superconductivity in such system, we showed how to engineer the proximity effect and we revealed a superconducting hard gap. Finally, we created a superconducting radio frequency driven ideal diode and a generator of non-sinusoidal current-phase relations. Our results open the path for the exploration of protected superconducting qubits and more complex hybrid devices in planar Germanium, like Kitaev chains and hybrid qubit devices. acknowledged_ssus: - _id: NanoFab - _id: M-Shop alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Marco full_name: Valentini, Marco id: C0BB2FAC-D767-11E9-B658-BC13E6697425 last_name: Valentini citation: ama: 'Valentini M. Mesoscopic phenomena in hybrid semiconductor-superconductor nanodevices : From full-shell nanowires to two-dimensional hole gas in germanium. 2023. doi:10.15479/at:ista:13286' apa: 'Valentini, M. (2023). Mesoscopic phenomena in hybrid semiconductor-superconductor nanodevices : From full-shell nanowires to two-dimensional hole gas in germanium. Institute of Science and Technology Austria. https://doi.org/10.15479/at:ista:13286' chicago: 'Valentini, Marco. “Mesoscopic Phenomena in Hybrid Semiconductor-Superconductor Nanodevices : From Full-Shell Nanowires to Two-Dimensional Hole Gas in Germanium.” Institute of Science and Technology Austria, 2023. https://doi.org/10.15479/at:ista:13286.' ieee: 'M. Valentini, “Mesoscopic phenomena in hybrid semiconductor-superconductor nanodevices : From full-shell nanowires to two-dimensional hole gas in germanium,” Institute of Science and Technology Austria, 2023.' ista: 'Valentini M. 2023. Mesoscopic phenomena in hybrid semiconductor-superconductor nanodevices : From full-shell nanowires to two-dimensional hole gas in germanium. Institute of Science and Technology Austria.' mla: 'Valentini, Marco. Mesoscopic Phenomena in Hybrid Semiconductor-Superconductor Nanodevices : From Full-Shell Nanowires to Two-Dimensional Hole Gas in Germanium. Institute of Science and Technology Austria, 2023, doi:10.15479/at:ista:13286.' short: 'M. Valentini, Mesoscopic Phenomena in Hybrid Semiconductor-Superconductor Nanodevices : From Full-Shell Nanowires to Two-Dimensional Hole Gas in Germanium, Institute of Science and Technology Austria, 2023.' date_created: 2023-07-24T14:10:45Z date_published: 2023-07-21T00:00:00Z date_updated: 2024-02-21T12:35:34Z day: '21' ddc: - '530' degree_awarded: PhD department: - _id: GradSch - _id: GeKa doi: 10.15479/at:ista:13286 ec_funded: 1 file: - access_level: closed checksum: 666ee31c7eade89679806287c062fa14 content_type: application/x-zip-compressed creator: mvalenti date_created: 2023-08-11T09:27:39Z date_updated: 2023-08-11T10:01:34Z file_id: '14033' file_name: PhD_thesis_Valentini_final.zip file_size: 56121429 relation: source_file - access_level: open_access checksum: 0992f2ebef152dee8e70055350ebbb55 content_type: application/pdf creator: mvalenti date_created: 2023-08-11T14:39:17Z date_updated: 2023-08-11T14:39:17Z file_id: '14035' file_name: PhD_thesis_Valentini_final_validated.pdf file_size: 38199711 relation: main_file file_date_updated: 2023-08-11T14:39:17Z has_accepted_license: '1' language: - iso: eng month: '07' oa: 1 oa_version: Published Version page: '184' project: - _id: 262116AA-B435-11E9-9278-68D0E5697425 name: Hybrid Semiconductor - Superconductor Quantum Devices - _id: 237E5020-32DE-11EA-91FC-C7463DDC885E call_identifier: H2020 grant_number: '862046' name: TOPOLOGICALLY PROTECTED AND SCALABLE QUANTUM BITS - _id: 34a66131-11ca-11ed-8bc3-a31681c6b03e grant_number: F8606 name: Conventional and unconventional topological superconductors publication_identifier: issn: - 2663 - 337X publication_status: published publisher: Institute of Science and Technology Austria related_material: record: - id: '13312' relation: part_of_dissertation status: public - id: '12118' relation: part_of_dissertation status: public - id: '8910' relation: part_of_dissertation status: public - id: '12522' relation: research_data status: public status: public supervisor: - first_name: Georgios full_name: Katsaros, Georgios id: 38DB5788-F248-11E8-B48F-1D18A9856A87 last_name: Katsaros orcid: 0000-0001-8342-202X title: 'Mesoscopic phenomena in hybrid semiconductor-superconductor nanodevices : From full-shell nanowires to two-dimensional hole gas in germanium' tmp: image: /images/cc_by_nc_sa.png legal_code_url: https://creativecommons.org/licenses/by-nc-sa/4.0/legalcode name: Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0) short: CC BY-NC-SA (4.0) type: dissertation user_id: 8b945eb4-e2f2-11eb-945a-df72226e66a9 year: '2023' ... --- _id: '13312' abstract: - lang: eng text: "Superconductor/semiconductor hybrid devices have attracted increasing\r\ninterest in the past years. Superconducting electronics aims to complement\r\nsemiconductor technology, while hybrid architectures are at the forefront of\r\nnew ideas such as topological superconductivity and protected qubits. In this\r\nwork, we engineer the induced superconductivity in two-dimensional germanium\r\nhole gas by varying the distance between the quantum well and the aluminum. We\r\ndemonstrate a hard superconducting gap and realize an electrically and flux\r\ntunable superconducting diode using a superconducting quantum interference\r\ndevice (SQUID). This allows to tune the current phase relation (CPR), to a\r\nregime where single Cooper pair tunneling is suppressed, creating a $ \\sin\r\n\\left( 2 \\varphi \\right)$ CPR. Shapiro experiments complement this\r\ninterpretation and the microwave drive allows to create a diode with $ \\approx\r\n100 \\%$ efficiency. The reported results open up the path towards monolithic\r\nintegration of spin qubit devices, microwave resonators and (protected)\r\nsuperconducting qubits on a silicon technology compatible platform." acknowledged_ssus: - _id: M-Shop - _id: NanoFab acknowledgement: "The authors acknowledge Alexander Brinkmann, Alessandro Crippa, Andrew Higginbotham, Andrea Iorio, Giordano\r\nScappucci and Christian Schonenberger for helpful discussions. We thank Marcel Verheijen for the support in the\r\nTEM analysis. This research and related results were made\r\npossible with the support of the NOMIS Foundation. It was\r\nsupported by the Scientific Service Units of ISTA through resources provided by the MIBA Machine Shop and the\r\nnanofabrication facility, the European Union’s Horizon 2020\r\nresearch and innovation programme under Grant Agreement\r\nNo 862046, the HORIZON-RIA 101069515 project and the\r\nFWF Projects #P-32235, #P-36507 and #F-8606. R.S.S.\r\nacknowledges Spanish CM “Talento Program” Project No.\r\n2022-T1/IND-24070." article_number: '2306.07109' article_processing_charge: No arxiv: 1 author: - first_name: Marco full_name: Valentini, Marco id: C0BB2FAC-D767-11E9-B658-BC13E6697425 last_name: Valentini - first_name: Oliver full_name: Sagi, Oliver id: 71616374-A8E9-11E9-A7CA-09ECE5697425 last_name: Sagi - first_name: Levon full_name: Baghumyan, Levon last_name: Baghumyan - first_name: Thijs de full_name: Gijsel, Thijs de last_name: Gijsel - first_name: Jason full_name: Jung, Jason id: 4C9ACE7A-F248-11E8-B48F-1D18A9856A87 last_name: Jung - first_name: Stefano full_name: Calcaterra, Stefano last_name: Calcaterra - first_name: Andrea full_name: Ballabio, Andrea last_name: Ballabio - first_name: Juan Aguilera full_name: Servin, Juan Aguilera last_name: Servin - first_name: Kushagra full_name: Aggarwal, Kushagra id: b22ab905-3539-11eb-84c3-fc159dcd79cb last_name: Aggarwal orcid: 0000-0001-9985-9293 - first_name: Marian full_name: Janik, Marian id: 396A1950-F248-11E8-B48F-1D18A9856A87 last_name: Janik - first_name: Thomas full_name: Adletzberger, Thomas id: 38756BB2-F248-11E8-B48F-1D18A9856A87 last_name: Adletzberger - first_name: Rubén Seoane full_name: Souto, Rubén Seoane last_name: Souto - first_name: Martin full_name: Leijnse, Martin last_name: Leijnse - first_name: Jeroen full_name: Danon, Jeroen last_name: Danon - first_name: Constantin full_name: Schrade, Constantin last_name: Schrade - first_name: Erik full_name: Bakkers, Erik last_name: Bakkers - first_name: Daniel full_name: Chrastina, Daniel last_name: Chrastina - first_name: Giovanni full_name: Isella, Giovanni last_name: Isella - first_name: Georgios full_name: Katsaros, Georgios id: 38DB5788-F248-11E8-B48F-1D18A9856A87 last_name: Katsaros orcid: 0000-0001-8342-202X citation: ama: Valentini M, Sagi O, Baghumyan L, et al. Radio frequency driven superconducting diode and parity conserving  Cooper pair transport in a two-dimensional germanium hole gas. arXiv. doi:10.48550/arXiv.2306.07109 apa: Valentini, M., Sagi, O., Baghumyan, L., Gijsel, T. de, Jung, J., Calcaterra, S., … Katsaros, G. (n.d.). Radio frequency driven superconducting diode and parity conserving  Cooper pair transport in a two-dimensional germanium hole gas. arXiv. https://doi.org/10.48550/arXiv.2306.07109 chicago: Valentini, Marco, Oliver Sagi, Levon Baghumyan, Thijs de Gijsel, Jason Jung, Stefano Calcaterra, Andrea Ballabio, et al. “Radio Frequency Driven Superconducting Diode and Parity Conserving  Cooper Pair Transport in a Two-Dimensional Germanium Hole Gas.” ArXiv, n.d. https://doi.org/10.48550/arXiv.2306.07109. ieee: M. Valentini et al., “Radio frequency driven superconducting diode and parity conserving  Cooper pair transport in a two-dimensional germanium hole gas,” arXiv. . ista: Valentini M, Sagi O, Baghumyan L, Gijsel T de, Jung J, Calcaterra S, Ballabio A, Servin JA, Aggarwal K, Janik M, Adletzberger T, Souto RS, Leijnse M, Danon J, Schrade C, Bakkers E, Chrastina D, Isella G, Katsaros G. Radio frequency driven superconducting diode and parity conserving  Cooper pair transport in a two-dimensional germanium hole gas. arXiv, 2306.07109. mla: Valentini, Marco, et al. “Radio Frequency Driven Superconducting Diode and Parity Conserving  Cooper Pair Transport in a Two-Dimensional Germanium Hole Gas.” ArXiv, 2306.07109, doi:10.48550/arXiv.2306.07109. short: M. Valentini, O. Sagi, L. Baghumyan, T. de Gijsel, J. Jung, S. Calcaterra, A. Ballabio, J.A. Servin, K. Aggarwal, M. Janik, T. Adletzberger, R.S. Souto, M. Leijnse, J. Danon, C. Schrade, E. Bakkers, D. Chrastina, G. Isella, G. Katsaros, ArXiv (n.d.). date_created: 2023-07-26T11:17:20Z date_published: 2023-06-13T00:00:00Z date_updated: 2024-02-07T07:52:32Z day: '13' ddc: - '530' department: - _id: GeKa - _id: M-Shop doi: 10.48550/arXiv.2306.07109 ec_funded: 1 external_id: arxiv: - '2306.07109' keyword: - Mesoscale and Nanoscale Physics language: - iso: eng main_file_link: - open_access: '1' url: https://doi.org/10.48550/arXiv.2306.07109 month: '06' oa: 1 oa_version: Preprint project: - _id: 237E5020-32DE-11EA-91FC-C7463DDC885E call_identifier: H2020 grant_number: '862046' name: TOPOLOGICALLY PROTECTED AND SCALABLE QUANTUM BITS - _id: 237B3DA4-32DE-11EA-91FC-C7463DDC885E call_identifier: FWF grant_number: P32235 name: Towards scalable hut wire quantum devices - _id: bd8bd29e-d553-11ed-ba76-f0070d4b237a grant_number: P36507 name: Merging spin and superconducting qubits in planar Ge - _id: 34a66131-11ca-11ed-8bc3-a31681c6b03e grant_number: F8606 name: Conventional and unconventional topological superconductors - _id: bd5b4ec5-d553-11ed-ba76-a6eedb083344 name: Protected states of quantum matter publication: arXiv publication_status: submitted related_material: record: - id: '13286' relation: dissertation_contains status: public status: public title: Radio frequency driven superconducting diode and parity conserving Cooper pair transport in a two-dimensional germanium hole gas tmp: image: /images/cc_by.png legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0) short: CC BY (4.0) type: preprint user_id: 8b945eb4-e2f2-11eb-945a-df72226e66a9 year: '2023' ...