Device contacts as spin-state selectors for silicon vacancies in 4H-SiC

Abstract

Optically addressable defect spins in semiconductors are promising building blocks for scalable quantum technologies. Yet, the consequences of conventional contact schemes used in semiconductor device integration for the quantum spin environment remain largely unexplored. Using the silicon vacancy (VSi) in silicon carbide (SiC) as a model system, we show that a widely used contact metal, nickel (Ni), intrinsically perturbs the defect spin state and quenches the characteristic emission from the spin-quartet channel of VSi. Low-energy muon spin rotation further reveals that Ni contacts create a magnetically contaminated region extending at least ∼110 nm into the SiC, in stark contrast to non-magnetic contacts such as Ti and Al. Moreover, cross-sectional cathodoluminescence measurements on samples with high defect density demonstrate a suppressed quartet-state luminescence from the VSi up to 500 nm beneath the Ni contact. This drastic influence on the defect's magnetic environment is accompanied by the appearance of a signature consistent with photoluminescence from the spin-doublet state of VSi under the Ni layer, which was absent in other material stacks. These results establish that standard device configurations can drive quantum defects into unwanted charge and spin configurations, underscoring the necessity of precise design to preserve quantum-grade spin environments in semiconductor devices.

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Cite

BibTeX RIS

BibTeX

@misc{teien2026device,
  title = {{Device contacts as spin-state selectors for silicon vacancies in 4H-SiC}},
  author = {Aurora Teien and Maria Mendes Martins and Andreas Gottscholl and Axel Erlebach and Piyush Kumar and Erlend Lemva Ousdal and Viktor Bobal and Augustinas Galeckas and Thomas Prokscha and Hannes Kraus and Corey J. Cochrane and Ulrike Grossner and Lasse Vines and Marianne Etzelmüller Bathen},
  howpublished = {arXiv},
  year = {2026},
  month = oct,
  doi = {10.48550/arxiv.2609.22845},
  eprint = {2609.22845},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2609.22845},
  note = {CC BY 4.0},
}

RIS

TY  - UNPB
TI  - Device contacts as spin-state selectors for silicon vacancies in 4H-SiC
AU  - Aurora Teien
AU  - Maria Mendes Martins
AU  - Andreas Gottscholl
AU  - Axel Erlebach
AU  - Piyush Kumar
AU  - Erlend Lemva Ousdal
AU  - Viktor Bobal
AU  - Augustinas Galeckas
AU  - Thomas Prokscha
AU  - Hannes Kraus
AU  - Corey J. Cochrane
AU  - Ulrike Grossner
AU  - Lasse Vines
AU  - Marianne Etzelmüller Bathen
PY  - 2026
DA  - 2026/10/14
PB  - arXiv
DO  - 10.48550/arxiv.2609.22845
UR  - https://arxiv.org/abs/2609.22845
AB  - Optically addressable defect spins in semiconductors are promising building blocks for scalable quantum technologies. Yet, the consequences of conventional contact schemes used in semiconductor device integration for the quantum spin environment remain largely unexplored. Using the silicon vacancy (V_Si) in silicon carbide (SiC) as a model system, we show that a widely used contact metal, nickel (Ni), intrinsically perturbs the defect spin state and quenches the characteristic emission from the spin-quartet channel of V_Si. Low-energy muon spin rotation further reveals that Ni contacts create a magnetically contaminated region extending at least ∼110 nm into the SiC, in stark contrast to non-magnetic contacts such as Ti and Al. Moreover, cross-sectional cathodoluminescence measurements on samples with high defect density demonstrate a suppressed quartet-state luminescence from the V_Si up to 500 nm beneath the Ni contact. This drastic influence on the defect's magnetic environment is accompanied by the appearance of a signature consistent with photoluminescence from the spin-doublet state of V_Si under the Ni layer, which was absent in other material stacks. These results establish that standard device configurations can drive quantum defects into unwanted charge and spin configurations, underscoring the necessity of precise design to preserve quantum-grade spin environments in semiconductor devices.
ER  -

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