---
_id: '14547'
abstract:
- lang: eng
  text: "Superconductor-semiconductor heterostructures currently capture a significant
    amount of research interest and they serve as the physical platform in many proposals
    towards topological quantum computation.\r\nDespite being under extensive investigations,
    historically using transport techniques, the basic properties of the interface
    between the superconductor and the semiconductor remain to be understood.\r\n\r\nIn
    this thesis, two separate studies on the Al-InAs heterostructures are reported
    with the first focusing on the physics of the material motivated by the emergence
    of a new phase, the Bogoliubov-Fermi surface. \r\nThe second focuses on a technological
    application, a gate-tunable Josephson parametric amplifier.\r\n\r\nIn the first
    study, we investigate the hypothesized unconventional nature of the induced superconductivity
    at the interface between the Al thin film and the InAs quantum well.\r\nWe embed
    a two-dimensional Al-InAs hybrid system in a resonant microwave circuit allowing
    measurements of change in inductance.\r\nThe behaviour of the resonance in a range
    of temperature and in-plane magnetic field has been studied and compared with
    the theory of conventional s-wave superconductor and a two-component theory that
    includes both contribution of the $s$-wave pairing in Al and the intraband $p
    \\pm ip$ pairing in InAs.\r\nMeasuring the temperature dependence of resonant
    frequency, no discrepancy is found between data and the conventional theory.\r\nWe
    observe the breakdown of superconductivity due to an applied magnetic field which
    contradicts the conventional theory.\r\nIn contrast, the data can be captured
    quantitatively by fitting to a two-component model.\r\nWe find the evidence of
    the intraband $p \\pm ip$ pairing in the InAs and the emergence of the Bogoliubov-Fermi
    surfaces due to magnetic field with the characteristic value $B^* = 0.33~\\mathrm{T}$.\r\nFrom
    the fits, the sheet resistance of Al, the carrier density and mobility in InAs
    are determined.\r\nBy systematically studying the anisotropy of the circuit response,
    we find weak anisotropy for $B < B^*$ and increasingly strong anisotropy for $B
    > B^*$ resulting in a pronounced two-lobe structure in polar plot of frequency
    versus field angle.\r\nStrong resemblance between the field dependence of dissipation
    and superfluid density hints at a hidden signature of the Bogoliubov-Fermi surface
    that is burried in the dissipation data.\r\n\r\nIn the second study, we realize
    a parametric amplifier with a Josephson field effect transistor as the active
    element.\r\nThe device's modest construction consists of a gated SNS weak link
    embedded at the center of a coplanar waveguide resonator.\r\nBy applying a gate
    voltage, the resonant frequency is field-effect tunable over a range of 2 GHz.\r\nModelling
    the JoFET minimally as a parallel RL circuit, the dissipation introduced by the
    JoFET can be quantitatively related to the gate voltage.\r\nWe observed gate-tunable
    Kerr nonlinearity qualitatively in line with expectation.\r\nThe JoFET amplifier
    has 20 dB of gain, 4 MHz of instantaneous bandwidth, and a 1dB compression point
    of -125.5 dBm when operated at a fixed resonant frequency.\r\nIn general, the
    signal-to-noise ratio is improved by 5-7 dB when the JoFET amplifier is activated
    compared.\r\nThe noise of the measurement chain and insertion loss of relevant
    circuit elements are calibrated to determine the expected and the real noise performance
    of the JoFET amplifier.\r\nAs a quantification of the noise performance, the measured
    total input-referred noise of the JoFET amplifier is in good agreement with the
    estimated expectation which takes device loss into account.\r\nWe found that the
    noise performance of the device reported in this document approaches one photon
    of total input-referred added noise which is the quantum limit imposed in nondegenerate
    parametric amplifier."
acknowledged_ssus:
- _id: NanoFab
- _id: Bio
alternative_title:
- ISTA Thesis
article_processing_charge: No
author:
- first_name: Duc T
  full_name: Phan, Duc T
  id: 29C8C0B4-F248-11E8-B48F-1D18A9856A87
  last_name: Phan
citation:
  ama: Phan DT. Resonant microwave spectroscopy of Al-InAs. 2023. doi:<a href="https://doi.org/10.15479/14547">10.15479/14547</a>
  apa: Phan, D. T. (2023). <i>Resonant microwave spectroscopy of Al-InAs</i>. Institute
    of Science and Technology Austria. <a href="https://doi.org/10.15479/14547">https://doi.org/10.15479/14547</a>
  chicago: Phan, Duc T. “Resonant Microwave Spectroscopy of Al-InAs.” Institute of
    Science and Technology Austria, 2023. <a href="https://doi.org/10.15479/14547">https://doi.org/10.15479/14547</a>.
  ieee: D. T. Phan, “Resonant microwave spectroscopy of Al-InAs,” Institute of Science
    and Technology Austria, 2023.
  ista: Phan DT. 2023. Resonant microwave spectroscopy of Al-InAs. Institute of Science
    and Technology Austria.
  mla: Phan, Duc T. <i>Resonant Microwave Spectroscopy of Al-InAs</i>. Institute of
    Science and Technology Austria, 2023, doi:<a href="https://doi.org/10.15479/14547">10.15479/14547</a>.
  short: D.T. Phan, Resonant Microwave Spectroscopy of Al-InAs, Institute of Science
    and Technology Austria, 2023.
date_created: 2023-11-17T13:45:26Z
date_published: 2023-11-16T00:00:00Z
date_updated: 2023-11-30T10:56:04Z
day: '16'
ddc:
- '530'
degree_awarded: PhD
department:
- _id: GradSch
- _id: AnHi
doi: 10.15479/14547
file:
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  checksum: db0c37d213bc002125bd59690e9db246
  content_type: application/pdf
  creator: pduc
  date_created: 2023-11-17T13:36:44Z
  date_updated: 2023-11-22T09:46:06Z
  file_id: '14548'
  file_name: Phan_Thesis_pdfa.pdf
  file_size: 34828019
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  checksum: 8d3bd6afa279a0078ffd13e06bb6d56d
  content_type: application/zip
  creator: pduc
  date_created: 2023-11-17T13:44:53Z
  date_updated: 2023-11-17T13:47:54Z
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  file_name: dissertation_src.zip
  file_size: 279319709
  relation: source_file
file_date_updated: 2023-11-22T09:46:06Z
has_accepted_license: '1'
keyword:
- superconductor-semiconductor
- superconductivity
- Al
- InAs
- p-wave
- superconductivity
- JPA
- microwave
language:
- iso: eng
month: '11'
oa: 1
oa_version: Published Version
page: '80'
publication_identifier:
  issn:
  - 2663 - 337X
publication_status: published
publisher: Institute of Science and Technology Austria
related_material:
  record:
  - id: '10851'
    relation: part_of_dissertation
    status: public
  - id: '13264'
    relation: part_of_dissertation
    status: public
status: public
supervisor:
- first_name: Andrew P
  full_name: Higginbotham, Andrew P
  id: 4AD6785A-F248-11E8-B48F-1D18A9856A87
  last_name: Higginbotham
  orcid: 0000-0003-2607-2363
title: Resonant microwave spectroscopy of Al-InAs
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'
...