---
_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
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'
...
---
_id: '10025'
abstract:
- lang: eng
text: Ferromagnetism is most common in transition metal compounds but may also arise
in low-density two-dimensional electron systems, with signatures observed in silicon,
III-V semiconductor systems, and graphene moiré heterostructures. Here we show
that gate-tuned van Hove singularities in rhombohedral trilayer graphene drive
the spontaneous ferromagnetic polarization of the electron system into one or
more spin- and valley flavors. Using capacitance measurements on graphite-gated
van der Waals heterostructures, we find a cascade of density- and electronic displacement
field tuned phase transitions marked by negative electronic compressibility. The
transitions define the boundaries between phases where quantum oscillations have
either four-fold, two-fold, or one-fold degeneracy, associated with a spin and
valley degenerate normal metal, spin-polarized `half-metal', and spin and valley
polarized `quarter metal', respectively. For electron doping, the salient features
are well captured by a phenomenological Stoner model with a valley-anisotropic
Hund's coupling, likely arising from interactions at the lattice scale. For hole
filling, we observe a richer phase diagram featuring a delicate interplay of broken
symmetries and transitions in the Fermi surface topology. Finally, by rotational
alignment of a hexagonal boron nitride substrate to induce a moiré superlattice,
we find that the superlattice perturbs the preexisting isospin order only weakly,
leaving the basic phase diagram intact while catalyzing the formation of topologically
nontrivial gapped states whenever itinerant half- or quarter metal states occur
at half- or quarter superlattice band filling. Our results show that rhombohedral
trilayer graphene is an ideal platform for well-controlled tests of many-body
theory and reveal magnetism in moiré materials to be fundamentally itinerant in
nature.
acknowledgement: "The authors acknowledge discussions with A. Macdonald, L. Fu, F.
Wang and M. Zaletel. AFY acknowledges support of the National Science Foundation
under DMR1654186, and the Gordon and Betty Moore Foundation under award GBMF9471.
The authors acknowledge the use of the research facilities within the California
NanoSystems Institute, supported by the University of California, Santa Barbara
and the University of California, Office of the President.\r\nK.W. and T.T. acknowledge
support from the Elemental Strategy Initiative conducted by the MEXT, Japan, Grant
Number JPMXP0112101001 and JSPS KAKENHI, Grant Number JP20H00354. EB and TH were
supported by the European Research Council (ERC) under grant HQMAT (Grant Agreement
No. 817799). A.G. acknowledges support by the European Unions Horizon 2020 research
and innovation program under the Marie Sklodowska-Curie Grant Agreement\r\nNo. 754411.\r\n"
article_processing_charge: No
article_type: original
author:
- first_name: Haoxin
full_name: Zhou, Haoxin
last_name: Zhou
- first_name: Tian
full_name: Xie, Tian
last_name: Xie
- first_name: Areg
full_name: Ghazaryan, Areg
id: 4AF46FD6-F248-11E8-B48F-1D18A9856A87
last_name: Ghazaryan
orcid: 0000-0001-9666-3543
- first_name: Tobias
full_name: Holder, Tobias
last_name: Holder
- first_name: James R.
full_name: Ehrets, James R.
last_name: Ehrets
- first_name: Eric M.
full_name: Spanton, Eric M.
last_name: Spanton
- first_name: Takashi
full_name: Taniguchi, Takashi
last_name: Taniguchi
- first_name: Kenji
full_name: Watanabe, Kenji
last_name: Watanabe
- first_name: Erez
full_name: Berg, Erez
last_name: Berg
- first_name: Maksym
full_name: Serbyn, Maksym
id: 47809E7E-F248-11E8-B48F-1D18A9856A87
last_name: Serbyn
orcid: 0000-0002-2399-5827
- first_name: Andrea F.
full_name: Young, Andrea F.
last_name: Young
citation:
ama: Zhou H, Xie T, Ghazaryan A, et al. Half and quarter metals in rhombohedral
trilayer graphene. Nature. 2021. doi:10.1038/s41586-021-03938-w
apa: Zhou, H., Xie, T., Ghazaryan, A., Holder, T., Ehrets, J. R., Spanton, E. M.,
… Young, A. F. (2021). Half and quarter metals in rhombohedral trilayer graphene.
Nature. Springer Nature. https://doi.org/10.1038/s41586-021-03938-w
chicago: Zhou, Haoxin, Tian Xie, Areg Ghazaryan, Tobias Holder, James R. Ehrets,
Eric M. Spanton, Takashi Taniguchi, et al. “Half and Quarter Metals in Rhombohedral
Trilayer Graphene.” Nature. Springer Nature, 2021. https://doi.org/10.1038/s41586-021-03938-w.
ieee: H. Zhou et al., “Half and quarter metals in rhombohedral trilayer graphene,”
Nature. Springer Nature, 2021.
ista: Zhou H, Xie T, Ghazaryan A, Holder T, Ehrets JR, Spanton EM, Taniguchi T,
Watanabe K, Berg E, Serbyn M, Young AF. 2021. Half and quarter metals in rhombohedral
trilayer graphene. Nature.
mla: Zhou, Haoxin, et al. “Half and Quarter Metals in Rhombohedral Trilayer Graphene.”
Nature, Springer Nature, 2021, doi:10.1038/s41586-021-03938-w.
short: H. Zhou, T. Xie, A. Ghazaryan, T. Holder, J.R. Ehrets, E.M. Spanton, T. Taniguchi,
K. Watanabe, E. Berg, M. Serbyn, A.F. Young, Nature (2021).
date_created: 2021-09-19T22:01:25Z
date_published: 2021-09-01T00:00:00Z
date_updated: 2023-08-14T07:04:06Z
day: '01'
department:
- _id: MaSe
- _id: MiLe
doi: 10.1038/s41586-021-03938-w
ec_funded: 1
external_id:
arxiv:
- '2104.00653'
isi:
- '000706977400002'
isi: 1
keyword:
- condensed matter - mesoscale and nanoscale physics
- condensed matter - strongly correlated electrons
- multidisciplinary
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://arxiv.org/abs/2104.00653
month: '09'
oa: 1
oa_version: Preprint
project:
- _id: 260C2330-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '754411'
name: ISTplus - Postdoctoral Fellowships
publication: Nature
publication_identifier:
eissn:
- 1476-4687
issn:
- 0028-0836
publication_status: published
publisher: Springer Nature
quality_controlled: '1'
related_material:
link:
- relation: erratum
url: https://doi.org/10.1038/s41586-021-04181-z
scopus_import: '1'
status: public
title: Half and quarter metals in rhombohedral trilayer graphene
type: journal_article
user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8
year: '2021'
...
---
_id: '9928'
abstract:
- lang: eng
text: There are two elementary superconducting qubit types that derive directly
from the quantum harmonic oscillator. In one, the inductor is replaced by a nonlinear
Josephson junction to realize the widely used charge qubits with a compact phase
variable and a discrete charge wave function. In the other, the junction is added
in parallel, which gives rise to an extended phase variable, continuous wave functions,
and a rich energy-level structure due to the loop topology. While the corresponding
rf superconducting quantum interference device Hamiltonian was introduced as a
quadratic quasi-one-dimensional potential approximation to describe the fluxonium
qubit implemented with long Josephson-junction arrays, in this work we implement
it directly using a linear superinductor formed by a single uninterrupted aluminum
wire. We present a large variety of qubits, all stemming from the same circuit
but with drastically different characteristic energy scales. This includes flux
and fluxonium qubits but also the recently introduced quasicharge qubit with strongly
enhanced zero-point phase fluctuations and a heavily suppressed flux dispersion.
The use of a geometric inductor results in high reproducibility of the inductive
energy as guaranteed by top-down lithography—a key ingredient for intrinsically
protected superconducting qubits.
acknowledged_ssus:
- _id: NanoFab
- _id: M-Shop
acknowledgement: We thank W. Hughes for analytic and numerical modeling during the
early stages of this work, J. Koch for discussions and support with the scqubits
package, R. Sett, P. Zielinski, and L. Drmic for software development, and G. Katsaros
for equipment support, as well as the MIBA workshop and the Institute of Science
and Technology Austria nanofabrication facility. We thank I. Pop, S. Deleglise,
and E. Flurin for discussions. This work was supported by a NOMIS Foundation research
grant, the Austrian Science Fund (FWF) through BeyondC (F7105), and IST Austria.
M.P. is the recipient of a Pöttinger scholarship at IST Austria. E.R. is the recipient
of a DOC fellowship of the Austrian Academy of Sciences at IST Austria.
article_processing_charge: No
article_type: original
author:
- first_name: Matilda
full_name: Peruzzo, Matilda
id: 3F920B30-F248-11E8-B48F-1D18A9856A87
last_name: Peruzzo
orcid: 0000-0002-3415-4628
- first_name: Farid
full_name: Hassani, Farid
id: 2AED110C-F248-11E8-B48F-1D18A9856A87
last_name: Hassani
orcid: 0000-0001-6937-5773
- first_name: Gregory
full_name: Szep, Gregory
last_name: Szep
- first_name: Andrea
full_name: Trioni, Andrea
id: 42F71B44-F248-11E8-B48F-1D18A9856A87
last_name: Trioni
- first_name: Elena
full_name: Redchenko, Elena
id: 2C21D6E8-F248-11E8-B48F-1D18A9856A87
last_name: Redchenko
- first_name: Martin
full_name: Zemlicka, Martin
id: 2DCF8DE6-F248-11E8-B48F-1D18A9856A87
last_name: Zemlicka
- first_name: Johannes M
full_name: Fink, Johannes M
id: 4B591CBA-F248-11E8-B48F-1D18A9856A87
last_name: Fink
orcid: 0000-0001-8112-028X
citation:
ama: 'Peruzzo M, Hassani F, Szep G, et al. Geometric superinductance qubits: Controlling
phase delocalization across a single Josephson junction. PRX Quantum. 2021;2(4):040341.
doi:10.1103/PRXQuantum.2.040341'
apa: 'Peruzzo, M., Hassani, F., Szep, G., Trioni, A., Redchenko, E., Zemlicka, M.,
& Fink, J. M. (2021). Geometric superinductance qubits: Controlling phase
delocalization across a single Josephson junction. PRX Quantum. American
Physical Society. https://doi.org/10.1103/PRXQuantum.2.040341'
chicago: 'Peruzzo, Matilda, Farid Hassani, Gregory Szep, Andrea Trioni, Elena Redchenko,
Martin Zemlicka, and Johannes M Fink. “Geometric Superinductance Qubits: Controlling
Phase Delocalization across a Single Josephson Junction.” PRX Quantum.
American Physical Society, 2021. https://doi.org/10.1103/PRXQuantum.2.040341.'
ieee: 'M. Peruzzo et al., “Geometric superinductance qubits: Controlling
phase delocalization across a single Josephson junction,” PRX Quantum,
vol. 2, no. 4. American Physical Society, p. 040341, 2021.'
ista: 'Peruzzo M, Hassani F, Szep G, Trioni A, Redchenko E, Zemlicka M, Fink JM.
2021. Geometric superinductance qubits: Controlling phase delocalization across
a single Josephson junction. PRX Quantum. 2(4), 040341.'
mla: 'Peruzzo, Matilda, et al. “Geometric Superinductance Qubits: Controlling Phase
Delocalization across a Single Josephson Junction.” PRX Quantum, vol. 2,
no. 4, American Physical Society, 2021, p. 040341, doi:10.1103/PRXQuantum.2.040341.'
short: M. Peruzzo, F. Hassani, G. Szep, A. Trioni, E. Redchenko, M. Zemlicka, J.M.
Fink, PRX Quantum 2 (2021) 040341.
date_created: 2021-08-17T08:14:18Z
date_published: 2021-11-24T00:00:00Z
date_updated: 2023-09-07T13:31:22Z
day: '24'
ddc:
- '530'
department:
- _id: JoFi
- _id: NanoFab
- _id: M-Shop
doi: 10.1103/PRXQuantum.2.040341
ec_funded: 1
external_id:
arxiv:
- '2106.05882'
isi:
- '000723015100001'
file:
- access_level: open_access
checksum: 36eb41ea43d8ca22b0efab12419e4eb2
content_type: application/pdf
creator: cchlebak
date_created: 2022-01-18T11:29:33Z
date_updated: 2022-01-18T11:29:33Z
file_id: '10641'
file_name: 2021_PRXQuantum_Peruzzo.pdf
file_size: 4247422
relation: main_file
success: 1
file_date_updated: 2022-01-18T11:29:33Z
has_accepted_license: '1'
intvolume: ' 2'
isi: 1
issue: '4'
keyword:
- quantum physics
- mesoscale and nanoscale physics
language:
- iso: eng
month: '11'
oa: 1
oa_version: Published Version
page: '040341'
project:
- _id: 26927A52-B435-11E9-9278-68D0E5697425
call_identifier: FWF
grant_number: F07105
name: Integrating superconducting quantum circuits
- _id: 2564DBCA-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '665385'
name: International IST Doctoral Program
- _id: 2622978C-B435-11E9-9278-68D0E5697425
name: Hybrid Semiconductor - Superconductor Quantum Devices
publication: PRX Quantum
publication_identifier:
eissn:
- 2691-3399
publication_status: published
publisher: American Physical Society
quality_controlled: '1'
related_material:
record:
- id: '13057'
relation: research_data
status: public
- id: '9920'
relation: dissertation_contains
status: public
scopus_import: '1'
status: public
title: 'Geometric superinductance qubits: Controlling phase delocalization across
a single Josephson junction'
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: 2
year: '2021'
...