发表机构
University of Oslo; ETH Zürich; Paul Scherrer Institute; California Institute of Technology; NASA Jet Propulsion Laboratory（奥斯陆大学; 苏黎世联邦理工学院; 保罗谢尔研究所; 加州理工学院; 美国国家航空航天局喷气推进实验室）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究以4H-SiC中硅空位为模型，发现镍接触会磁污染并猝灭其四重态发光，而钛和铝无此效应，凸显器件接触设计对保持量子自旋环境的关键作用。
AI 中文摘要
宽禁带半导体中光学可寻址的缺陷自旋是构建可扩展量子技术的有前景的组成部分。然而，半导体器件集成中使用的常规接触方案对量子自旋环境的影响在很大程度上仍未得到探索。以碳化硅（SiC）中的硅空位（V$\mathrm{Si}$）作为模型系统，我们展示了一种广泛使用的接触金属——镍（Ni）——本质上扰动缺陷自旋态，并猝灭V$\mathrm{Si}$自旋四重态通道的特征发射。低能μ子自旋旋转进一步揭示，Ni接触在SiC中产生一个磁污染区域，延伸至少约120 nm，与非磁性接触（如Ti和Al）形成鲜明对比。此外，对具有高缺陷密度盒状轮廓的样品进行的横截面阴极发光测量表明，在Ni接触下方长达500 nm的距离内，V$\mathrm{Si}$的四重态发光受到抑制。这种对缺陷磁环境的剧烈影响伴随着在Ni层附近出现与V$\mathrm{Si}$自旋二重态光致发光一致的特征，而在其他材料堆叠中未观察到该特征。这些结果表明，即使是标准的器件配置也能将量子缺陷驱动到不需要的电荷和自旋配置中，强调了在半导体器件中保持量子级自旋环境需要精确设计的必要性。
英文摘要
Optically addressable defect spins in wide band gap 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$_\mathrm{Si}$) 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$_\mathrm{Si}$. Low-energy muon spin rotation further reveals that Ni contacts create a magnetically contaminated region extending at least $\sim$120 nm into the SiC, in stark contrast to non-magnetic contacts such as Ti and Al. Moreover, cross-sectional cathodoluminescence measurements conducted on samples with box profiles of high defect density demonstrate a suppression of the quartet-state luminescence from the V$_\mathrm{Si}$ over a distance 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$_\mathrm{Si}$ in the vicinity of the Ni layer, which was not observed in other material stacks. These results establish that even 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.
