Chemical modification using only small amounts of elements such as Zn, In, Sb, or Ni has proven to be an effective means to control the desirable crystal structure of hexagonal $\eta \text{−}\mathrm{C}{\mathrm{u}}_6\mathrm{S}{\mathrm{n}}_5$ over a wide thermally operating window, typically found in Pb-free Sn-based soldering or Li-ion battery anode applications. Though appealing, the underlying mechanisms on the role of these dopants remain incomplete and their atomic arrangements within the $\eta \text{−}\mathrm{C}{\mathrm{u}}_6\mathrm{S}{\mathrm{n}}_5$ lattices have not yet been experimentally determined. In the current study, we directly reveal the atomic positions of Zn, In, and Sb at the Sn sites of $\eta \text{−}\mathrm{C}{\mathrm{u}}_6\mathrm{S}{\mathrm{n}}_5$ via atomic-scale x-ray energy dispersive spectroscopy (XEDS) maps utilizing advanced Cs-corrected scanning transmission electron microscopy. The use of advanced statistical algorithms including Poisson non-local principal component analysis and lattice averaging enables the fine resolution of weak XEDS maps from trace dopant elements. Our first-principles calculations further identify the influence of dopants at these atomic sites on the overall energetics, electronic structures, as well as local bonding environments, leading to the most favorable situations for $\eta \text{−}\mathrm{C}{\mathrm{u}}_6\mathrm{S}{\mathrm{n}}_5$ stabilization.

中文翻译：

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微量掺杂剂的原子位置及其在η-Cu6Sn5稳定中的作用

已证明仅使用少量元素（例如Zn，In，Sb或Ni）进行化学修饰是控制所需六方晶结构的有效手段 $\eta \text{-}\mathrm{C}{\mathrm{ü}}_6\mathrm{小号}{\mathrm{ñ}}_5$通常在无铅锡基焊接或锂离子电池负极应用中发现的热工作范围广。尽管具有吸引力，但有关这些掺杂剂作用的基本机制仍然不完整，并且它们在原子内的原子排列$\eta \text{-}\mathrm{C}{\mathrm{ü}}_6\mathrm{小号}{\mathrm{ñ}}_5$晶格尚未通过实验确定。在当前的研究中，我们直接揭示了Zn，In和Sb在Sn原子处的原子位置。$\eta \text{-}\mathrm{C}{\mathrm{ü}}_6\mathrm{小号}{\mathrm{ñ}}_5$通过原子尺度的X射线能量色散光谱（XEDS）图，利用先进的Cs校正的扫描透射电子显微镜。使用包括Poisson非局部主成分分析和晶格平均在内的高级统计算法，可以从痕量掺杂元素中精细分辨弱XEDS图。我们的第一性原理计算进一步确定了这些原子位点处的掺杂剂对整体能量学，电子结构以及局部键合环境的影响，从而导致了最有利的情况。$\eta \text{-}\mathrm{C}{\mathrm{ü}}_6\mathrm{小号}{\mathrm{ñ}}_5$ 稳定。