---
_id: '10920'
abstract:
- lang: eng
  text: The spin-orbit interaction permits to control the state of a spin qubit via
    electric fields. For holes it is particularly strong, allowing for fast all electrical
    qubit manipulation, and yet an in-depth understanding of this interaction in hole
    systems is missing. Here we investigate, experimentally and theoretically, the
    effect of the cubic Rashba spin-orbit interaction on the mixing of the spin states
    by studying singlet-triplet oscillations in a planar Ge hole double quantum dot.
    Landau-Zener sweeps at different magnetic field directions allow us to disentangle
    the effects of the spin-orbit induced spin-flip term from those caused by strongly
    site-dependent and anisotropic quantum dot g tensors. Our work, therefore, provides
    new insights into the hole spin-orbit interaction, necessary for optimizing future
    qubit experiments.
acknowledged_ssus:
- _id: M-Shop
- _id: NanoFab
acknowledgement: "This research was supported by the Scientific Service Units of ISTA
  through resources provided by the MIBA Machine Shop and the nanofabrication facility.
  This project has received funding from the European Union’s Horizon 2020 research
  and innovation program under the Marie\r\nSkłodowska-Curie Grant Agreement No. 844511,
  No. 75441, and by the FWF-P 30207, I05060, and M3032-N projects. A. B. acknowledges
  support from the EU Horizon-2020 FET project microSPIRE, ID: 766955. P.M. M. and
  G. B. acknowledge funding by the Deutsche Forschungsgemeinschaft (DFG—German Research
  Foundation) under Project No. 450396347. This work was supported by the Royal Society
  (URF\\R1\\191150) and the European Research Council (Grant Agreement No. 948932),
  N. A. acknowledges the use of the University of Oxford Advanced Research Computing
  (ARC) facility."
article_number: '126803'
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Daniel
  full_name: Jirovec, Daniel
  id: 4C473F58-F248-11E8-B48F-1D18A9856A87
  last_name: Jirovec
  orcid: 0000-0002-7197-4801
- first_name: Philipp M.
  full_name: Mutter, Philipp M.
  last_name: Mutter
- first_name: Andrea C
  full_name: Hofmann, Andrea C
  id: 340F461A-F248-11E8-B48F-1D18A9856A87
  last_name: Hofmann
- first_name: Alessandro
  full_name: Crippa, Alessandro
  id: 1F2B21A2-F6E7-11E9-9B82-F7DBE5697425
  last_name: Crippa
  orcid: 0000-0002-2968-611X
- first_name: Marek
  full_name: Rychetsky, Marek
  last_name: Rychetsky
- first_name: David L.
  full_name: Craig, David L.
  last_name: Craig
- first_name: Josip
  full_name: Kukucka, Josip
  id: 3F5D8856-F248-11E8-B48F-1D18A9856A87
  last_name: Kukucka
- first_name: Frederico
  full_name: Martins, Frederico
  id: 38F80F9A-1CB8-11EA-BC76-B49B3DDC885E
  last_name: Martins
  orcid: 0000-0003-2668-2401
- first_name: Andrea
  full_name: Ballabio, Andrea
  last_name: Ballabio
- first_name: Natalia
  full_name: Ares, Natalia
  last_name: Ares
- first_name: Daniel
  full_name: Chrastina, Daniel
  last_name: Chrastina
- first_name: Giovanni
  full_name: Isella, Giovanni
  last_name: Isella
- first_name: 'Guido '
  full_name: 'Burkard, Guido '
  last_name: Burkard
- first_name: Georgios
  full_name: Katsaros, Georgios
  id: 38DB5788-F248-11E8-B48F-1D18A9856A87
  last_name: Katsaros
citation:
  ama: Jirovec D, Mutter PM, Hofmann AC, et al. Dynamics of hole singlet-triplet qubits
    with large g-factor differences. <i>Physical Review Letters</i>. 2022;128(12).
    doi:<a href="https://doi.org/10.1103/PhysRevLett.128.126803">10.1103/PhysRevLett.128.126803</a>
  apa: Jirovec, D., Mutter, P. M., Hofmann, A. C., Crippa, A., Rychetsky, M., Craig,
    D. L., … Katsaros, G. (2022). Dynamics of hole singlet-triplet qubits with large
    g-factor differences. <i>Physical Review Letters</i>. American Physical Society.
    <a href="https://doi.org/10.1103/PhysRevLett.128.126803">https://doi.org/10.1103/PhysRevLett.128.126803</a>
  chicago: Jirovec, Daniel, Philipp M. Mutter, Andrea C Hofmann, Alessandro Crippa,
    Marek Rychetsky, David L. Craig, Josip Kukucka, et al. “Dynamics of Hole Singlet-Triplet
    Qubits with Large g-Factor Differences.” <i>Physical Review Letters</i>. American
    Physical Society, 2022. <a href="https://doi.org/10.1103/PhysRevLett.128.126803">https://doi.org/10.1103/PhysRevLett.128.126803</a>.
  ieee: D. Jirovec <i>et al.</i>, “Dynamics of hole singlet-triplet qubits with large
    g-factor differences,” <i>Physical Review Letters</i>, vol. 128, no. 12. American
    Physical Society, 2022.
  ista: Jirovec D, Mutter PM, Hofmann AC, Crippa A, Rychetsky M, Craig DL, Kukucka
    J, Martins F, Ballabio A, Ares N, Chrastina D, Isella G, Burkard G, Katsaros G.
    2022. Dynamics of hole singlet-triplet qubits with large g-factor differences.
    Physical Review Letters. 128(12), 126803.
  mla: Jirovec, Daniel, et al. “Dynamics of Hole Singlet-Triplet Qubits with Large
    g-Factor Differences.” <i>Physical Review Letters</i>, vol. 128, no. 12, 126803,
    American Physical Society, 2022, doi:<a href="https://doi.org/10.1103/PhysRevLett.128.126803">10.1103/PhysRevLett.128.126803</a>.
  short: D. Jirovec, P.M. Mutter, A.C. Hofmann, A. Crippa, M. Rychetsky, D.L. Craig,
    J. Kukucka, F. Martins, A. Ballabio, N. Ares, D. Chrastina, G. Isella, G. Burkard,
    G. Katsaros, Physical Review Letters 128 (2022).
date_created: 2022-03-24T15:51:11Z
date_published: 2022-03-24T00:00:00Z
date_updated: 2023-08-03T06:14:58Z
day: '24'
ddc:
- '530'
department:
- _id: GradSch
- _id: GeKa
doi: 10.1103/PhysRevLett.128.126803
ec_funded: 1
external_id:
  arxiv:
  - '2111.05130'
  isi:
  - '000786542500004'
file:
- access_level: open_access
  checksum: 6e66ad548d18db9c131f304acbd5a1f4
  content_type: application/pdf
  creator: dernst
  date_created: 2022-03-28T06:53:39Z
  date_updated: 2022-03-28T06:53:39Z
  file_id: '10928'
  file_name: 2022_PhysRevLetters_Jirovec.pdf
  file_size: 1266515
  relation: main_file
  success: 1
file_date_updated: 2022-03-28T06:53:39Z
has_accepted_license: '1'
intvolume: '       128'
isi: 1
issue: '12'
language:
- iso: eng
month: '03'
oa: 1
oa_version: Published Version
project:
- _id: 26A151DA-B435-11E9-9278-68D0E5697425
  call_identifier: H2020
  grant_number: '844511'
  name: Majorana bound states in Ge/SiGe heterostructures
- _id: 260C2330-B435-11E9-9278-68D0E5697425
  call_identifier: H2020
  grant_number: '754411'
  name: ISTplus - Postdoctoral Fellowships
- _id: 2641CE5E-B435-11E9-9278-68D0E5697425
  call_identifier: FWF
  grant_number: P30207
  name: Hole spin orbit qubits in Ge quantum wells
- _id: c0977eea-5a5b-11eb-8a69-a862db0cf4d1
  grant_number: I05060
  name: High impedance circuit quantum electrodynamics with hole spins
- _id: c08c05c4-5a5b-11eb-8a69-dc6ce49d7973
  grant_number: M03032
  name: Long-range spin exchange for 2D qubits architectures
publication: Physical Review Letters
publication_identifier:
  eissn:
  - 1079-7114
publication_status: published
publisher: American Physical Society
quality_controlled: '1'
status: public
title: Dynamics of hole singlet-triplet qubits with large g-factor differences
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: 4359f0d1-fa6c-11eb-b949-802e58b17ae8
volume: 128
year: '2022'
...
---
_id: '8909'
abstract:
- lang: eng
  text: Spin qubits are considered to be among the most promising candidates for building
    a quantum processor. Group IV hole spin qubits have moved into the focus of interest
    due to the ease of operation and compatibility with Si technology. In addition,
    Ge offers the option for monolithic superconductor-semiconductor integration.
    Here we demonstrate a hole spin qubit operating at fields below 10 mT, the critical
    field of Al, by exploiting the large out-of-plane hole g-factors in planar Ge
    and by encoding the qubit into the singlet-triplet states of a double quantum
    dot. We observe electrically controlled X and Z-rotations with tunable frequencies
    exceeding 100 MHz and dephasing times of 1μs which we extend beyond 15μs with
    echo techniques. These results show that Ge hole singlet triplet qubits outperform
    their electronic Si and GaAs based counterparts in speed and coherence, respectively.
    In addition, they are on par with Ge single spin qubits, but can be operated at
    much lower fields underlining their potential for on chip integration with superconducting
    technologies.
acknowledged_ssus:
- _id: M-Shop
- _id: NanoFab
acknowledgement: This research was supported by the Scientific Service Units of Institute
  of Science and Technology (IST) Austria through resources provided by the Miba Machine
  Shop and the nanofabrication facility, and was made possible with the support of
  the NOMIS Foundation. This project has received funding from the European Union’s
  Horizon 2020 research and innovation programme under Marie Sklodowska-Curie grant
  agreements no. 844511 and no. 75441, and by the Austrian Science Fund FWF-P 30207
  project. A.B. acknowledges support from the European Union Horizon 2020 FET project
  microSPIRE, no. 766955. M. Botifoll and J.A. acknowledge funding from Generalitat
  de Catalunya 2017 SGR 327. The Catalan Institute of Nanoscience and Nanotechnology
  (ICN2) is supported by the Severo Ochoa programme from the Spanish Ministery of
  Economy (MINECO) (grant no. SEV-2017-0706) and is funded by the Catalonian Research
  Centre (CERCA) Programme, Generalitat de Catalunya. Part of the present work has
  been performed within the framework of the Universitat Autónoma de Barcelona Materials
  Science PhD programme. Part of the HAADF scanning transmission electron microscopy
  was conducted in the Laboratorio de Microscopias Avanzadas at Instituto de Nanociencia
  de Aragon, Universidad de Zaragoza. ICN2 acknowledge support from the Spanish Superior
  Council of Scientific Research (CSIC) Research Platform on Quantum Technologies
  PTI-001. M.B. acknowledges funding from the Catalan Agency for Management of University
  and Research Grants (AGAUR) Generalitat de Catalunya formation of investigators
  (FI) PhD grant.
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Daniel
  full_name: Jirovec, Daniel
  id: 4C473F58-F248-11E8-B48F-1D18A9856A87
  last_name: Jirovec
  orcid: 0000-0002-7197-4801
- first_name: Andrea C
  full_name: Hofmann, Andrea C
  id: 340F461A-F248-11E8-B48F-1D18A9856A87
  last_name: Hofmann
- first_name: Andrea
  full_name: Ballabio, Andrea
  last_name: Ballabio
- first_name: Philipp M.
  full_name: Mutter, Philipp M.
  last_name: Mutter
- first_name: Giulio
  full_name: Tavani, Giulio
  last_name: Tavani
- first_name: Marc
  full_name: Botifoll, Marc
  last_name: Botifoll
- first_name: Alessandro
  full_name: Crippa, Alessandro
  id: 1F2B21A2-F6E7-11E9-9B82-F7DBE5697425
  last_name: Crippa
  orcid: 0000-0002-2968-611X
- first_name: Josip
  full_name: Kukucka, Josip
  id: 3F5D8856-F248-11E8-B48F-1D18A9856A87
  last_name: Kukucka
- first_name: Oliver
  full_name: Sagi, Oliver
  id: 71616374-A8E9-11E9-A7CA-09ECE5697425
  last_name: Sagi
- first_name: Frederico
  full_name: Martins, Frederico
  id: 38F80F9A-1CB8-11EA-BC76-B49B3DDC885E
  last_name: Martins
  orcid: 0000-0003-2668-2401
- first_name: Jaime
  full_name: Saez Mollejo, Jaime
  id: e0390f72-f6e0-11ea-865d-862393336714
  last_name: Saez Mollejo
- first_name: Ivan
  full_name: Prieto Gonzalez, Ivan
  id: 2A307FE2-F248-11E8-B48F-1D18A9856A87
  last_name: Prieto Gonzalez
  orcid: 0000-0002-7370-5357
- first_name: Maksim
  full_name: Borovkov, Maksim
  id: 2ac7a0a2-3562-11eb-9256-fbd18ea55087
  last_name: Borovkov
- first_name: Jordi
  full_name: Arbiol, Jordi
  last_name: Arbiol
- 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: Jirovec D, Hofmann AC, Ballabio A, et al. A singlet triplet hole spin qubit
    in planar Ge. <i>Nature Materials</i>. 2021;20(8):1106–1112. doi:<a href="https://doi.org/10.1038/s41563-021-01022-2">10.1038/s41563-021-01022-2</a>
  apa: Jirovec, D., Hofmann, A. C., Ballabio, A., Mutter, P. M., Tavani, G., Botifoll,
    M., … Katsaros, G. (2021). A singlet triplet hole spin qubit in planar Ge. <i>Nature
    Materials</i>. Springer Nature. <a href="https://doi.org/10.1038/s41563-021-01022-2">https://doi.org/10.1038/s41563-021-01022-2</a>
  chicago: Jirovec, Daniel, Andrea C Hofmann, Andrea Ballabio, Philipp M. Mutter,
    Giulio Tavani, Marc Botifoll, Alessandro Crippa, et al. “A Singlet Triplet Hole
    Spin Qubit in Planar Ge.” <i>Nature Materials</i>. Springer Nature, 2021. <a href="https://doi.org/10.1038/s41563-021-01022-2">https://doi.org/10.1038/s41563-021-01022-2</a>.
  ieee: D. Jirovec <i>et al.</i>, “A singlet triplet hole spin qubit in planar Ge,”
    <i>Nature Materials</i>, vol. 20, no. 8. Springer Nature, pp. 1106–1112, 2021.
  ista: Jirovec D, Hofmann AC, Ballabio A, Mutter PM, Tavani G, Botifoll M, Crippa
    A, Kukucka J, Sagi O, Martins F, Saez Mollejo J, Prieto Gonzalez I, Borovkov M,
    Arbiol J, Chrastina D, Isella G, Katsaros G. 2021. A singlet triplet hole spin
    qubit in planar Ge. Nature Materials. 20(8), 1106–1112.
  mla: Jirovec, Daniel, et al. “A Singlet Triplet Hole Spin Qubit in Planar Ge.” <i>Nature
    Materials</i>, vol. 20, no. 8, Springer Nature, 2021, pp. 1106–1112, doi:<a href="https://doi.org/10.1038/s41563-021-01022-2">10.1038/s41563-021-01022-2</a>.
  short: D. Jirovec, A.C. Hofmann, A. Ballabio, P.M. Mutter, G. Tavani, M. Botifoll,
    A. Crippa, J. Kukucka, O. Sagi, F. Martins, J. Saez Mollejo, I. Prieto Gonzalez,
    M. Borovkov, J. Arbiol, D. Chrastina, G. Isella, G. Katsaros, Nature Materials
    20 (2021) 1106–1112.
date_created: 2020-12-02T10:50:47Z
date_published: 2021-08-01T00:00:00Z
date_updated: 2024-03-25T23:30:14Z
day: '01'
department:
- _id: GeKa
- _id: NanoFab
- _id: GradSch
doi: 10.1038/s41563-021-01022-2
ec_funded: 1
external_id:
  arxiv:
  - '2011.13755'
  isi:
  - '000657596400001'
intvolume: '        20'
isi: 1
issue: '8'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://arxiv.org/abs/2011.13755
month: '08'
oa: 1
oa_version: Preprint
page: 1106–1112
project:
- _id: 26A151DA-B435-11E9-9278-68D0E5697425
  call_identifier: H2020
  grant_number: '844511'
  name: Majorana bound states in Ge/SiGe heterostructures
- _id: 260C2330-B435-11E9-9278-68D0E5697425
  call_identifier: H2020
  grant_number: '754411'
  name: ISTplus - Postdoctoral Fellowships
- _id: 2641CE5E-B435-11E9-9278-68D0E5697425
  call_identifier: FWF
  grant_number: P30207
  name: Hole spin orbit qubits in Ge quantum wells
- _id: 262116AA-B435-11E9-9278-68D0E5697425
  name: Hybrid Semiconductor - Superconductor Quantum Devices
publication: Nature Materials
publication_identifier:
  eissn:
  - 1476-4660
  issn:
  - 1476-1122
publication_status: published
publisher: Springer Nature
quality_controlled: '1'
related_material:
  link:
  - description: News on IST Homepage
    relation: press_release
    url: https://ist.ac.at/en/news/quantum-computing-with-holes/
  record:
  - id: '9323'
    relation: research_data
    status: public
  - id: '10058'
    relation: dissertation_contains
    status: public
scopus_import: '1'
status: public
title: A singlet triplet hole spin qubit in planar Ge
type: journal_article
user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8
volume: 20
year: '2021'
...
---
_id: '8911'
abstract:
- lang: eng
  text: "In the worldwide endeavor for disruptive quantum technologies, germanium
    is emerging as a versatile material to realize devices capable of encoding, processing,
    or transmitting quantum information. These devices leverage special properties
    of the germanium valence-band states, commonly known as holes, such as their inherently
    strong spin-orbit coupling and the ability to host superconducting pairing correlations.
    In this Review, we initially introduce the physics of holes in low-dimensional
    germanium structures with key insights from a theoretical perspective. We then
    examine the material science progress underpinning germanium-based planar heterostructures
    and nanowires. We review the most significant experimental results demonstrating
    key building blocks for quantum technology, such as an electrically driven universal
    quantum gate set with spin qubits in quantum dots and superconductor-semiconductor
    devices for hybrid quantum systems. We conclude by identifying the most promising
    prospects\r\ntoward scalable quantum information processing. "
acknowledgement: "G.S., M.W.,F.A.Z acknowledge financial support from The Netherlands
  Organization for Scientific Research (NWO). F.Z., D.L., G.K. acknowledge funding
  from the European Union’s Horizon 2020 research and innovation programme under Grand
  Agreement Nr. 862046. G.K. acknowledges funding from FP7 ERC Starting Grant 335497,
  FWF Y 715-N30, FWF P-30207. S.D. acknowledges support from the European Union’s
  Horizon 2020 program under Grant\r\nAgreement No. 81050 and from the Agence Nationale
  de la Recherche through the TOPONANO and CMOSQSPIN projects. J.Z. acknowledges support
  from the National Key R&D Program of China (Grant No. 2016YFA0301701) and Strategic
  Priority Research Program of CAS (Grant No. XDB30000000). D.L. and C.K. acknowledge
  the Swiss National Science Foundation and NCCR QSIT."
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Giordano
  full_name: Scappucci, Giordano
  last_name: Scappucci
- first_name: Christoph
  full_name: Kloeffel, Christoph
  last_name: Kloeffel
- first_name: Floris A.
  full_name: Zwanenburg, Floris A.
  last_name: Zwanenburg
- first_name: Daniel
  full_name: Loss, Daniel
  last_name: Loss
- first_name: Maksym
  full_name: Myronov, Maksym
  last_name: Myronov
- first_name: Jian-Jun
  full_name: Zhang, Jian-Jun
  last_name: Zhang
- first_name: Silvano De
  full_name: Franceschi, Silvano De
  last_name: Franceschi
- first_name: Georgios
  full_name: Katsaros, Georgios
  id: 38DB5788-F248-11E8-B48F-1D18A9856A87
  last_name: Katsaros
  orcid: 0000-0001-8342-202X
- first_name: Menno
  full_name: Veldhorst, Menno
  last_name: Veldhorst
citation:
  ama: Scappucci G, Kloeffel C, Zwanenburg FA, et al. The germanium quantum information
    route. <i>Nature Reviews Materials</i>. 2021;6:926–943. doi:<a href="https://doi.org/10.1038/s41578-020-00262-z">10.1038/s41578-020-00262-z</a>
  apa: Scappucci, G., Kloeffel, C., Zwanenburg, F. A., Loss, D., Myronov, M., Zhang,
    J.-J., … Veldhorst, M. (2021). The germanium quantum information route. <i>Nature
    Reviews Materials</i>. Springer Nature. <a href="https://doi.org/10.1038/s41578-020-00262-z">https://doi.org/10.1038/s41578-020-00262-z</a>
  chicago: Scappucci, Giordano, Christoph Kloeffel, Floris A. Zwanenburg, Daniel Loss,
    Maksym Myronov, Jian-Jun Zhang, Silvano De Franceschi, Georgios Katsaros, and
    Menno Veldhorst. “The Germanium Quantum Information Route.” <i>Nature Reviews
    Materials</i>. Springer Nature, 2021. <a href="https://doi.org/10.1038/s41578-020-00262-z">https://doi.org/10.1038/s41578-020-00262-z</a>.
  ieee: G. Scappucci <i>et al.</i>, “The germanium quantum information route,” <i>Nature
    Reviews Materials</i>, vol. 6. Springer Nature, pp. 926–943, 2021.
  ista: Scappucci G, Kloeffel C, Zwanenburg FA, Loss D, Myronov M, Zhang J-J, Franceschi
    SD, Katsaros G, Veldhorst M. 2021. The germanium quantum information route. Nature
    Reviews Materials. 6, 926–943.
  mla: Scappucci, Giordano, et al. “The Germanium Quantum Information Route.” <i>Nature
    Reviews Materials</i>, vol. 6, Springer Nature, 2021, pp. 926–943, doi:<a href="https://doi.org/10.1038/s41578-020-00262-z">10.1038/s41578-020-00262-z</a>.
  short: G. Scappucci, C. Kloeffel, F.A. Zwanenburg, D. Loss, M. Myronov, J.-J. Zhang,
    S.D. Franceschi, G. Katsaros, M. Veldhorst, Nature Reviews Materials 6 (2021)
    926–943.
date_created: 2020-12-02T10:52:51Z
date_published: 2021-10-01T00:00:00Z
date_updated: 2024-03-07T14:48:57Z
day: '01'
department:
- _id: GeKa
doi: 10.1038/s41578-020-00262-z
ec_funded: 1
external_id:
  arxiv:
  - '2004.08133'
  isi:
  - '000600826100003'
intvolume: '         6'
isi: 1
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://arxiv.org/abs/2004.08133
month: '10'
oa: 1
oa_version: Preprint
page: '926–943 '
project:
- _id: 25517E86-B435-11E9-9278-68D0E5697425
  call_identifier: FP7
  grant_number: '335497'
  name: Towards Spin qubits and Majorana fermions in Germanium selfassembled hut-wires
- _id: 2552F888-B435-11E9-9278-68D0E5697425
  call_identifier: FWF
  grant_number: Y00715
  name: Loch Spin-Qubits und Majorana-Fermionen in Germanium
- _id: 2641CE5E-B435-11E9-9278-68D0E5697425
  call_identifier: FWF
  grant_number: P30207
  name: Hole spin orbit qubits in Ge quantum wells
publication: Nature Reviews Materials
publication_identifier:
  eissn:
  - 2058-8437
publication_status: published
publisher: Springer Nature
quality_controlled: '1'
scopus_import: '1'
status: public
title: The germanium quantum information route
type: journal_article
user_id: 3E5EF7F0-F248-11E8-B48F-1D18A9856A87
volume: 6
year: '2021'
...
---
_id: '10058'
abstract:
- lang: eng
  text: 'Quantum information and computation has become a vast field paved with opportunities
    for researchers and investors. As large multinational companies and international
    funds are heavily investing in quantum technologies it is still a question which
    platform is best suited for the task of realizing a scalable quantum processor.
    In this work we investigate hole spins in Ge quantum wells. These hold great promise
    as they possess several favorable properties: a small effective mass, a strong
    spin-orbit coupling, long relaxation time and an inherent immunity to hyperfine
    noise. All these characteristics helped Ge hole spin qubits to evolve from a single
    qubit to a fully entangled four qubit processor in only 3 years. Here, we investigated
    a qubit approach leveraging the large out-of-plane g-factors of heavy hole states
    in Ge quantum dots. We found this qubit to be reproducibly operable at extremely
    low magnetic field and at large speeds while maintaining coherence. This was possible
    because large differences of g-factors in adjacent dots can be achieved in the
    out-of-plane direction. In the in-plane direction the small g-factors, on the
    other hand, can be altered very effectively by the confinement potentials. Here,
    we found that this can even lead to a sign change of the g-factors. The resulting
    g-factor difference alters the dynamics of the system drastically and produces
    effects typically attributed to a spin-orbit induced spin-flip term.  The investigations
    carried out in this thesis give further insights into the possibilities of holes
    in Ge and reveal new physical properties that need to be considered when designing
    future spin qubit experiments.'
acknowledged_ssus:
- _id: M-Shop
- _id: NanoFab
acknowledgement: The author gratefully acknowledges support by the Austrian Science
  Fund (FWF), grants No P30207, and the Nomis foundation.
alternative_title:
- ISTA Thesis
article_processing_charge: No
author:
- first_name: Daniel
  full_name: Jirovec, Daniel
  id: 4C473F58-F248-11E8-B48F-1D18A9856A87
  last_name: Jirovec
  orcid: 0000-0002-7197-4801
citation:
  ama: Jirovec D. Singlet-Triplet qubits and spin-orbit interaction in 2-dimensional
    Ge hole gases. 2021. doi:<a href="https://doi.org/10.15479/at:ista:10058">10.15479/at:ista:10058</a>
  apa: Jirovec, D. (2021). <i>Singlet-Triplet qubits and spin-orbit interaction in
    2-dimensional Ge hole gases</i>. Institute of Science and Technology Austria.
    <a href="https://doi.org/10.15479/at:ista:10058">https://doi.org/10.15479/at:ista:10058</a>
  chicago: Jirovec, Daniel. “Singlet-Triplet Qubits and Spin-Orbit Interaction in
    2-Dimensional Ge Hole Gases.” Institute of Science and Technology Austria, 2021.
    <a href="https://doi.org/10.15479/at:ista:10058">https://doi.org/10.15479/at:ista:10058</a>.
  ieee: D. Jirovec, “Singlet-Triplet qubits and spin-orbit interaction in 2-dimensional
    Ge hole gases,” Institute of Science and Technology Austria, 2021.
  ista: Jirovec D. 2021. Singlet-Triplet qubits and spin-orbit interaction in 2-dimensional
    Ge hole gases. Institute of Science and Technology Austria.
  mla: Jirovec, Daniel. <i>Singlet-Triplet Qubits and Spin-Orbit Interaction in 2-Dimensional
    Ge Hole Gases</i>. Institute of Science and Technology Austria, 2021, doi:<a href="https://doi.org/10.15479/at:ista:10058">10.15479/at:ista:10058</a>.
  short: D. Jirovec, Singlet-Triplet Qubits and Spin-Orbit Interaction in 2-Dimensional
    Ge Hole Gases, Institute of Science and Technology Austria, 2021.
date_created: 2021-09-30T07:53:49Z
date_published: 2021-10-05T00:00:00Z
date_updated: 2023-09-08T11:41:08Z
day: '05'
ddc:
- '621'
- '539'
degree_awarded: PhD
department:
- _id: GradSch
- _id: GeKa
doi: 10.15479/at:ista:10058
file:
- access_level: closed
  checksum: ad6bcb24083ed7c02baaf1885c9ea3d5
  content_type: application/x-zip-compressed
  creator: djirovec
  date_created: 2021-09-30T14:29:14Z
  date_updated: 2022-12-20T23:30:07Z
  embargo_to: open_access
  file_id: '10061'
  file_name: PHD_Thesis_Jirovec_Source.zip
  file_size: 32397600
  relation: source_file
- access_level: open_access
  checksum: 5fbe08d4f66d1153e04c47971538fae8
  content_type: application/pdf
  creator: djirovec
  date_created: 2021-10-05T07:56:49Z
  date_updated: 2022-12-20T23:30:07Z
  embargo: 2022-10-06
  file_id: '10087'
  file_name: PHD_Thesis_pdfa2b_1.pdf
  file_size: 26910829
  relation: main_file
file_date_updated: 2022-12-20T23:30:07Z
has_accepted_license: '1'
keyword:
- qubits
- quantum computing
- holes
language:
- iso: eng
month: '10'
oa: 1
oa_version: Published Version
page: '151'
project:
- _id: 2641CE5E-B435-11E9-9278-68D0E5697425
  call_identifier: FWF
  grant_number: P30207
  name: Hole spin orbit qubits in Ge quantum wells
publication_identifier:
  issn:
  - 2663-337X
publication_status: published
publisher: Institute of Science and Technology Austria
related_material:
  record:
  - id: '8831'
    relation: part_of_dissertation
    status: public
  - id: '10065'
    relation: part_of_dissertation
    status: public
  - id: '10066'
    relation: part_of_dissertation
    status: public
  - id: '8909'
    relation: part_of_dissertation
    status: public
  - id: '5816'
    relation: part_of_dissertation
    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: Singlet-Triplet qubits and spin-orbit interaction in 2-dimensional Ge hole
  gases
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: dissertation
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
year: '2021'
...
---
_id: '10066'
abstract:
- lang: eng
  text: The potential of Si and SiGe-based devices for the scaling of quantum circuits
    is tainted by device variability. Each device needs to be tuned to operation conditions.
    We give a key step towards tackling this variability with an algorithm that, without
    modification, is capable of tuning a 4-gate Si FinFET, a 5-gate GeSi nanowire
    and a 7-gate SiGe heterostructure double quantum dot device from scratch. We achieve
    tuning times of 30, 10, and 92 minutes, respectively. The algorithm also provides
    insight into the parameter space landscape for each of these devices. These results
    show that overarching solutions for the tuning of quantum devices are enabled
    by machine learning.
acknowledged_ssus:
- _id: NanoFab
acknowledgement: "We acknowledge Ang Li, Erik P. A. M. Bakkers (University of Eindhoven)
  for the fabrication of the Ge/Si nanowire. This work was supported by the Royal
  Society, the EPSRC National Quantum Technology Hub in Networked Quantum Information
  Technology (EP/M013243/1), Quantum Technology Capital (EP/N014995/1), EPSRC Platform
  Grant\r\n(EP/R029229/1), the European Research Council (Grant agreement 948932),
  the Swiss Nanoscience Institute, the\r\nNCCR SPIN, the EU H2020 European Microkelvin
  Platform EMP grant No. 824109, the Scientific Service Units\r\nof IST Austria through
  resources provided by the nanofabrication facility and, the FWF-P30207 project.
  This publication was also made possible through support from Templeton World Charity
  Foundation and John Templeton Foundation. The opinions expressed in this publication
  are those of the authors and do not necessarily reflect the views of the Templeton
  Foundations."
article_number: '2107.12975'
article_processing_charge: No
arxiv: 1
author:
- first_name: B.
  full_name: Severin, B.
  last_name: Severin
- first_name: D. T.
  full_name: Lennon, D. T.
  last_name: Lennon
- first_name: L. C.
  full_name: Camenzind, L. C.
  last_name: Camenzind
- first_name: F.
  full_name: Vigneau, F.
  last_name: Vigneau
- first_name: F.
  full_name: Fedele, F.
  last_name: Fedele
- first_name: Daniel
  full_name: Jirovec, Daniel
  id: 4C473F58-F248-11E8-B48F-1D18A9856A87
  last_name: Jirovec
  orcid: 0000-0002-7197-4801
- first_name: A.
  full_name: Ballabio, A.
  last_name: Ballabio
- first_name: D.
  full_name: Chrastina, D.
  last_name: Chrastina
- first_name: G.
  full_name: Isella, G.
  last_name: Isella
- first_name: M. de
  full_name: Kruijf, M. de
  last_name: Kruijf
- first_name: M. J.
  full_name: Carballido, M. J.
  last_name: Carballido
- first_name: S.
  full_name: Svab, S.
  last_name: Svab
- first_name: A. V.
  full_name: Kuhlmann, A. V.
  last_name: Kuhlmann
- first_name: F. R.
  full_name: Braakman, F. R.
  last_name: Braakman
- first_name: S.
  full_name: Geyer, S.
  last_name: Geyer
- first_name: F. N. M.
  full_name: Froning, F. N. M.
  last_name: Froning
- first_name: H.
  full_name: Moon, H.
  last_name: Moon
- first_name: M. A.
  full_name: Osborne, M. A.
  last_name: Osborne
- first_name: D.
  full_name: Sejdinovic, D.
  last_name: Sejdinovic
- first_name: Georgios
  full_name: Katsaros, Georgios
  id: 38DB5788-F248-11E8-B48F-1D18A9856A87
  last_name: Katsaros
  orcid: 0000-0001-8342-202X
- first_name: D. M.
  full_name: Zumbühl, D. M.
  last_name: Zumbühl
- first_name: G. A. D.
  full_name: Briggs, G. A. D.
  last_name: Briggs
- first_name: N.
  full_name: Ares, N.
  last_name: Ares
citation:
  ama: Severin B, Lennon DT, Camenzind LC, et al. Cross-architecture tuning of silicon
    and SiGe-based quantum devices using machine learning. <i>arXiv</i>. doi:<a href="https://doi.org/10.48550/arXiv.2107.12975">10.48550/arXiv.2107.12975</a>
  apa: Severin, B., Lennon, D. T., Camenzind, L. C., Vigneau, F., Fedele, F., Jirovec,
    D., … Ares, N. (n.d.). Cross-architecture tuning of silicon and SiGe-based quantum
    devices using machine learning. <i>arXiv</i>. <a href="https://doi.org/10.48550/arXiv.2107.12975">https://doi.org/10.48550/arXiv.2107.12975</a>
  chicago: Severin, B., D. T. Lennon, L. C. Camenzind, F. Vigneau, F. Fedele, Daniel
    Jirovec, A. Ballabio, et al. “Cross-Architecture Tuning of Silicon and SiGe-Based
    Quantum Devices Using Machine Learning.” <i>ArXiv</i>, n.d. <a href="https://doi.org/10.48550/arXiv.2107.12975">https://doi.org/10.48550/arXiv.2107.12975</a>.
  ieee: B. Severin <i>et al.</i>, “Cross-architecture tuning of silicon and SiGe-based
    quantum devices using machine learning,” <i>arXiv</i>. .
  ista: Severin B, Lennon DT, Camenzind LC, Vigneau F, Fedele F, Jirovec D, Ballabio
    A, Chrastina D, Isella G, Kruijf M de, Carballido MJ, Svab S, Kuhlmann AV, Braakman
    FR, Geyer S, Froning FNM, Moon H, Osborne MA, Sejdinovic D, Katsaros G, Zumbühl
    DM, Briggs GAD, Ares N. Cross-architecture tuning of silicon and SiGe-based quantum
    devices using machine learning. arXiv, 2107.12975.
  mla: Severin, B., et al. “Cross-Architecture Tuning of Silicon and SiGe-Based Quantum
    Devices Using Machine Learning.” <i>ArXiv</i>, 2107.12975, doi:<a href="https://doi.org/10.48550/arXiv.2107.12975">10.48550/arXiv.2107.12975</a>.
  short: B. Severin, D.T. Lennon, L.C. Camenzind, F. Vigneau, F. Fedele, D. Jirovec,
    A. Ballabio, D. Chrastina, G. Isella, M. de Kruijf, M.J. Carballido, S. Svab,
    A.V. Kuhlmann, F.R. Braakman, S. Geyer, F.N.M. Froning, H. Moon, M.A. Osborne,
    D. Sejdinovic, G. Katsaros, D.M. Zumbühl, G.A.D. Briggs, N. Ares, ArXiv (n.d.).
date_created: 2021-10-01T12:40:22Z
date_published: 2021-07-27T00:00:00Z
date_updated: 2024-03-25T23:30:14Z
day: '27'
department:
- _id: GeKa
doi: 10.48550/arXiv.2107.12975
external_id:
  arxiv:
  - '2107.12975'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://doi.org/10.48550/arXiv.2107.12975
month: '07'
oa: 1
oa_version: Preprint
project:
- _id: 2641CE5E-B435-11E9-9278-68D0E5697425
  call_identifier: FWF
  grant_number: P30207
  name: Hole spin orbit qubits in Ge quantum wells
publication: arXiv
publication_status: submitted
related_material:
  record:
  - id: '10058'
    relation: dissertation_contains
    status: public
status: public
title: Cross-architecture tuning of silicon and SiGe-based quantum devices using machine
  learning
type: preprint
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
year: '2021'
...
---
_id: '10065'
abstract:
- lang: eng
  text: We study double quantum dots in a Ge/SiGe heterostructure and test their maturity
    towards singlet-triplet ($S-T_0$) qubits. We demonstrate a large range of tunability,
    from two single quantum dots to a double quantum dot. We measure Pauli spin blockade
    and study the anisotropy of the $g$-factor. We use an adjacent quantum dot for
    sensing charge transitions in the double quantum dot at interest. In conclusion,
    Ge/SiGe possesses all ingredients necessary for building a singlet-triplet qubit.
acknowledged_ssus:
- _id: M-Shop
- _id: NanoFab
acknowledgement: "We thank Matthias Brauns for helpful discussions and careful proofreading
  of the manuscript. This project has received funding from the European Union’s Horizon
  2020 research and innovation program under the Marie Sklodowska-Curie grant agreement
  No 844511 and from the FWF project P30207. The research was supported by the Scientific
  Service Units of IST Austria through resources provided by the MIBA machine shop
  and the nanofabrication\r\nfacility."
article_number: '1910.05841'
article_processing_charge: No
arxiv: 1
author:
- first_name: Andrea C
  full_name: Hofmann, Andrea C
  id: 340F461A-F248-11E8-B48F-1D18A9856A87
  last_name: Hofmann
- first_name: Daniel
  full_name: Jirovec, Daniel
  id: 4C473F58-F248-11E8-B48F-1D18A9856A87
  last_name: Jirovec
  orcid: 0000-0002-7197-4801
- first_name: Maxim
  full_name: Borovkov, Maxim
  last_name: Borovkov
- first_name: Ivan
  full_name: Prieto Gonzalez, Ivan
  id: 2A307FE2-F248-11E8-B48F-1D18A9856A87
  last_name: Prieto Gonzalez
  orcid: 0000-0002-7370-5357
- first_name: Andrea
  full_name: Ballabio, Andrea
  last_name: Ballabio
- first_name: Jacopo
  full_name: Frigerio, Jacopo
  last_name: Frigerio
- 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: Hofmann AC, Jirovec D, Borovkov M, et al. Assessing the potential of Ge/SiGe
    quantum dots as hosts for singlet-triplet qubits. <i>arXiv</i>. doi:<a href="https://doi.org/10.48550/arXiv.1910.05841">10.48550/arXiv.1910.05841</a>
  apa: Hofmann, A. C., Jirovec, D., Borovkov, M., Prieto Gonzalez, I., Ballabio, A.,
    Frigerio, J., … Katsaros, G. (n.d.). Assessing the potential of Ge/SiGe quantum
    dots as hosts for singlet-triplet qubits. <i>arXiv</i>. <a href="https://doi.org/10.48550/arXiv.1910.05841">https://doi.org/10.48550/arXiv.1910.05841</a>
  chicago: Hofmann, Andrea C, Daniel Jirovec, Maxim Borovkov, Ivan Prieto Gonzalez,
    Andrea Ballabio, Jacopo Frigerio, Daniel Chrastina, Giovanni Isella, and Georgios
    Katsaros. “Assessing the Potential of Ge/SiGe Quantum Dots as Hosts for Singlet-Triplet
    Qubits.” <i>ArXiv</i>, n.d. <a href="https://doi.org/10.48550/arXiv.1910.05841">https://doi.org/10.48550/arXiv.1910.05841</a>.
  ieee: A. C. Hofmann <i>et al.</i>, “Assessing the potential of Ge/SiGe quantum dots
    as hosts for singlet-triplet qubits,” <i>arXiv</i>. .
  ista: Hofmann AC, Jirovec D, Borovkov M, Prieto Gonzalez I, Ballabio A, Frigerio
    J, Chrastina D, Isella G, Katsaros G. Assessing the potential of Ge/SiGe quantum
    dots as hosts for singlet-triplet qubits. arXiv, 1910.05841.
  mla: Hofmann, Andrea C., et al. “Assessing the Potential of Ge/SiGe Quantum Dots
    as Hosts for Singlet-Triplet Qubits.” <i>ArXiv</i>, 1910.05841, doi:<a href="https://doi.org/10.48550/arXiv.1910.05841">10.48550/arXiv.1910.05841</a>.
  short: A.C. Hofmann, D. Jirovec, M. Borovkov, I. Prieto Gonzalez, A. Ballabio, J.
    Frigerio, D. Chrastina, G. Isella, G. Katsaros, ArXiv (n.d.).
date_created: 2021-10-01T12:14:51Z
date_published: 2019-10-13T00:00:00Z
date_updated: 2024-03-25T23:30:14Z
day: '13'
department:
- _id: GeKa
doi: 10.48550/arXiv.1910.05841
ec_funded: 1
external_id:
  arxiv:
  - '1910.05841'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://arxiv.org/abs/1910.05841
month: '10'
oa: 1
oa_version: Preprint
project:
- _id: 26A151DA-B435-11E9-9278-68D0E5697425
  call_identifier: H2020
  grant_number: '844511'
  name: Majorana bound states in Ge/SiGe heterostructures
- _id: 2641CE5E-B435-11E9-9278-68D0E5697425
  call_identifier: FWF
  grant_number: P30207
  name: Hole spin orbit qubits in Ge quantum wells
publication: arXiv
publication_status: submitted
related_material:
  record:
  - id: '10058'
    relation: dissertation_contains
    status: public
status: public
title: Assessing the potential of Ge/SiGe quantum dots as hosts for singlet-triplet
  qubits
type: preprint
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
year: '2019'
...