$^{111}$In(→$^{111}$Cd)掺杂α-Al$_2$O$_3$单晶中'后效应'现象：结合实验双模型分析与密度泛函理论的新方法
"Aftereffects'' Phenomenon in $^{111}$In($\rightarrow$$^{111}$Cd)-Implanted $α$-Al$_2$O$_3$ Single Crystals: Novel Approach Integrating Experimental Double-Model Analysis with Density-Functional Theory
AI总结：
研究通过结合实验双模型分析与DFT，探讨动态超精细相互作用的起源，揭示了不同电荷态下Cd掺杂对EFG的影响，解释了'后效应'现象的动态机制。
摘要：
我们开发了一种实验双模型分析，结合密度泛函理论（DFT），以探索动态超精细相互作用（HFIs）的起源，这些相互作用与电子捕获衰变'后效应'（ECAE）现象相关。这种电子效应可逆地随温度变化，在氧化物中掺杂$^{111}$In（EC→$^{111}$Cd）探测原子的时差扰动γ-γ角相关性（TDPAC）实验中已被观测到。除了确定动态过程结束后稳定最终电场梯度（EFG）的电子配置，我们还确定了探测核周围初始配置及其对应的EFGs，其波动产生这些动态HFIs。我们证明了两种最广泛用于分析此类动态HFI的方法参数的等价性，使我们能够在每个温度下获得这些初始电子配置。在此框架内，为了解释$^{111}$In掺杂α-Al$_2$O$_3$单晶报道的有争议的TDPAC结果，我们对Cd掺杂α-Al$_2$O$_3$进行了DFT研究，考察其缺陷形成能作为Cd杂质水平电荷态函数。我们显示，预期相互作用HFI$_u$的稳定最终EFG起源于$^{111}$Cd探测器位于无捕获电子空穴的缺陷自由替代Al位点（在所有测量温度下）。那些意外的HFI$_d$起源于Al位点的探测器，但具有不同的Cd杂质水平占据程度。我们显示，对于HFI$_u$，一个被捕获的空穴，而对于HFI$_d$，至少五个空穴负责动态阶段，当'后效应'更显著时。所提出的场景解释了动态阶段未结束时观察到的明确EFG。
英文摘要：
We develop an experimental double-model analysis, combined with density-functional theory (DFT), to explore the origins of dynamic hyperfine interactions (HFIs) linked to the electron-capture decay ''aftereffects ''(ECAE) phenomenon. This electronic effect, reversible with temperature, has been observed in time-differential perturbed $γ$-$γ$ angular correlations (TDPAC) experiments on oxides doped with ($^{111}$In (EC)$\rightarrow$)$^{111}$Cd probe atoms. Besides identifying the electronic configuration that yields the stable final electric-field gradient (EFG) after the dynamic process ends, we determine the initial configurations around the probe nucleus and their corresponding EFGs whose fluctuations produce these dynamic HFIs. We demonstrate the equivalence between parameters of the two most widely used methods for analyzing this type of dynamic HFI, enabling us to obtain these initial electronic configurations at each temperature. In this framework, to unravel controversial TDPAC results reported for $^{111}$In-implanted $α$-Al$_2$O$_3$ single crystals, we perform a DFT study of Cd-doped $α$-Al$_2$O$_3$, examining their defect-formation energies, as functions of the Cd impurity level's charge state. We show that the stable final EFG for the expected interaction HFI$_u$ originates from $^{111}$Cd probes located at defect-free substitutional Al sites (without trapped electron holes) across all measured temperatures. Those of the unexpected HFI$_d$ originate from probes at Al sites, but with different degrees of occupation of the Cd impurity level. We show that one trapped hole for HFI$_u$ and at least five for HFI$_d$ are responsible for the dynamic regime when the ''aftereffects'' are more pronounced. The proposed scenario accounts for the observation of well-defined EFGs when the dynamic regime does not end.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
