立方Ce$^{3+}$晶场交叉中的应变控制拓扑与量子调控
Strain-controlled topology and quantum control at a cubic Ce$^{3+}$ crystal-field crossing
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中文总结 AI 辅助
本文提出一个基于对称性的框架，证明立方Ce$^{3+}$中磁场诱导的晶场交叉可通过应变和磁场控制产生具有单位陈数的拓扑结构，为稀土系统的高场量子调控提供了新途径。
中文摘要 AI 辅助
场调谐的晶场交叉为在局域稀土自由度中实现合成拓扑提供了一条途径，前提是能够通过对称性分辨的微扰独立控制交叉态。本文证明，立方Ce$^{3+}$中由场诱导的交叉恰好具有这种结构。对于$B\parallel[001]$，交叉受二重旋转保护，而$T_{2g}$剪切应变$\epsilon_{xz}$和$\epsilon_{yz}$破坏该保护，并通过正交的赝自旋分量混合两个态。结合磁场失谐，这些控制在三维参数空间中产生一个具有单位大小陈数的孤立双锥点。利用CeTe晶场尺度，得到理想的单离子交叉场约为$35.5$ T。经过校准的点电荷计算给出代表性的投影剪切耦合$|\alpha_{T_{2g}}|\simeq18.1$ meV每单位张量应变，对应于$0.10\\%$和$0.20\\%$张量剪切下$0.036$和$0.072$ meV的能隙。我们识别了相关的弹性和磁学特征，讨论了静电估算在杂化Ce化合物中的局限性，并确定了循环几何控制的绝热和相干性要求。结果是一个基于对称性的框架，将稀土系统中的高场晶场重构、应变响应和参数空间拓扑联系起来。
英文摘要
Field-tuned crystal-field crossings provide a route to synthetic topology in localized rare-earth degrees of freedom when symmetry-resolved perturbations can independently control the crossing states. Here we show that a field-induced crossing in cubic Ce$^{3+}$ has precisely this structure. For $B\parallel[001]$, the crossing is protected by a twofold rotation, while the $T_{2g}$ shears $ε_{xz}$ and $ε_{yz}$ break that protection and mix the two states through orthogonal pseudospin components. Together with magnetic-field detuning, these controls generate an isolated diabolical point with unit-magnitude Chern charge in a three-dimensional parameter space. Using the CeTe crystal-field scale gives an ideal single-ion crossing near $35.5$ T. A calibrated point-charge calculation gives a representative projected shear coupling $|α_{T_{2g}}|\simeq18.1$ meV per unit tensor strain, corresponding to gaps of $0.036$ and $0.072$ meV for tensor shears of $0.10\%$ and $0.20\%$. We identify the associated elastic and magnetic signatures, discuss the limitations of the electrostatic estimate in a hybridizing Ce compound, and determine the adiabatic and coherence requirements for cyclic geometric control. The result is a symmetry-based framework that connects high-field crystal-field reconstruction, strain response, and parameter-space topology in rare-earth systems.
发表机构
- Department of Physics and Astronomy, University of North Florida（北佛罗里达大学物理与天文学系）
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