Single atom magnets offer the possibility of magnetic information storage in the most fundamental unit of matter. Identifying the parameters that control the stability of their magnetic states is crucial to design novel quantum magnets with tailored properties. Here, we use X-ray absorption spectroscopy to show that the electronic configuration of dysprosium atoms on MgO(100) thin films can be tuned by the proximity of the metal Ag(100) substrate onto which the MgO films are grown. Increasing the MgO thickness from 2.5 to 9 monolayers induces a change in the dysprosium electronic configuration from 4f⁹ to 4f¹⁰. Hysteresis loops indicate long magnetic lifetimes for both configurations, however, with a different field-dependent magnetic stability. Combining these measurements with scanning tunneling microscopy, density functional theory, and multiplet calculations unveils the role of the adsorption site and charge transfer to the substrate in determining the stability of quantum states in dysprosium single atom magnets.

中文翻译：

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镝单原子磁铁中电子结构与磁稳定性的相关性

单原子磁铁提供了在最基本的物质单位中存储磁性信息的可能性。确定控制其磁态稳定性的参数对于设计具有定制特性的新型量子磁体至关重要。在这里，我们使用 X 射线吸收光谱来表明 MgO(100) 薄膜上镝原子的电子构型可以通过靠近金属 Ag(100) 衬底来调整，MgO 薄膜生长在该衬底上。将 MgO 厚度从 2.5 增加到 9 个单层会导致镝电子配置从 4f ⁹到 4f ^{10 的变化}. 磁滞回线表明两种配置都有较长的磁寿命，但具有不同的场相关磁稳定性。将这些测量与扫描隧道显微镜、密度泛函理论和多重态计算相结合，揭示了吸附位点和电荷转移到基板在确定镝单原子磁体中量子态稳定性方面的作用。