KIT | KIT-Bibliothek | Impressum | Datenschutz

Probing Hundreds of Individual Quantum Defects in Polycrystalline and Amorphous Alumina

Hung, Chih-Chiao; Yu, Liuqi; Foroozani, Neda; Fritz, Stefan 1; Gerthsen, Dagmar 1; Osborn, Kevin D.
1 Laboratorium für Elektronenmikroskopie (LEM), Karlsruher Institut für Technologie (KIT)

Abstract:

Quantum two-level systems (TLSs) are present in the materials of qubits and are considered defects because they limit qubit coherence. For superconducting qubits, the quintessential Josephson junction barrier is made of amorphous alumina, which hosts TLSs. However, TLSs are not understood generally -- either structurally or in atomic composition. In this study, we greatly extend the quantitative data available on TLSs by reporting on the physical dipole moment in two alumina types: polycrystalline γ−Al2O3 and amorphous a−AlOx. To obtain the dipole moments pz, rather from the less-structural coupling parameter g, we tune individual TLSs with an external electric field to extract the pz of the TLSs in a cavity QED system. We find a clear difference in the dipole moment distribution from the film types, indicating a difference in TLS structures. A large sample of approximately 400 individual TLSs are analyzed from the polycrystalline film type. Their dipoles along the growth direction pz have a mean value of 2.6±0.3 Debye (D) and standard deviation σ = 1.6±0.2 D . The material distribution fits well to a single Gaussian function. ... mehr

Zugehörige Institution(en) am KIT Laboratorium für Elektronenmikroskopie (LEM)
Publikationstyp Zeitschriftenaufsatz
Publikationsmonat/-jahr 03.2022
Sprache Englisch
Identifikator ISSN: 2331-7019, 2331-7043
KITopen-ID: 1000144607
Erschienen in Physical Review Applied
Verlag American Physical Society (APS)
Band 17
Heft 3
Seiten Art.-Nr.: 034025
Vorab online veröffentlicht am 09.03.2022
Nachgewiesen in Scopus
Dimensions
Web of Science
OpenAlex
Relationen in KITopen

Verlagsausgabe §
DOI: 10.5445/IR/1000144607
Veröffentlicht am 12.04.2022
Originalveröffentlichung
DOI: 10.1103/PhysRevApplied.17.034025
Scopus
Zitationen: 12
Web of Science
Zitationen: 14
Dimensions
Zitationen: 13
Seitenaufrufe: 84
seit 14.04.2022
Downloads: 51
seit 30.04.2022
Cover der Publikation
KIT – Die Forschungsuniversität in der Helmholtz-Gemeinschaft
KITopen Landing Page