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arXiv 2108.00141cond-mat.str-el
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（Eu $_{1-x}$ Ca $_{x}$）$_{2}$ Ir $_{2}$ O $_{7}$在金属-绝缘体转变过程中的结构、磁性和电子行为

Mapping the structural, magnetic and electronic behavior of (Eu$_{1-x}$Ca$_{x}$)$_{2}$Ir$_{2}$O$_{7}$ across a metal-insulator transition

E. Zoghlin, Z. Porter, S. Britner, S. Husremovic, Y. Choi, D. Haskel, G. Laurita, S. D. Wilson

备注：
18 pages, 10 figures
发表信息：
J. Phys.: Condens. Matter 33.5 (2020): 055601
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摘要：

在这项研究中，我们采用体电子性质表征和X-射线散射/光谱技术映射的结构，磁性和电子性质的（Eu $_{1-x}$ Ca $_{x}$）$_{2}$ Ir $_{2}$ O $_{7}$作为钙掺杂的函数。正如预期的那样，金属-绝缘体转变温度$T_{MIT}$随着Ca掺杂而降低，直到实现金属态降至2 K。与此相反，$T_{AFM}$成为去耦从MIT和（可能是短程）AFM秩序持续到金属制度。这种解耦被理解为电子相分离状态的开始的结果，其发生似乎取决于合成方法和稀土位点磁性。PDF分析表明，发生电子相分离没有伴随的化学相分离或变化的短程晶体对称性，而同步辐射X射线衍射证实，有没有变化的长程晶体对称性。X射线吸收测量证实了（Eu $_{1-x}$ Ca $_{x}$）$_{2}$ Ir $_{2}$ O $_{7}$的$J_{eff}$ = 1/2特征。令人惊讶的是，这些测量也表明净电子掺杂，而不是预期的空穴掺杂，表明补偿机制。最后，XMCD测量表明，在很大程度上不受Ca掺杂的弱Ir磁极化。

英文摘要：

In this study, we employ bulk electronic properties characterization and x-ray scattering/spectroscopy techniques to map the structural, magnetic and electronic properties of (Eu$_{1-x}$Ca$_{x}$)$_{2}$Ir$_{2}$O$_{7}$ as a function of Ca-doping. As expected, the metal-insulator transition temperature, $T_{MIT}$, decreases with Ca-doping until a metallic state is realized down to 2 K. In contrast, $T_{AFM}$ becomes decoupled from the MIT and (likely short-range) AFM order persists into the metallic regime. This decoupling is understood as a result of the onset of an electronically phase separated state, the occurrence of which seemingly depends on both synthesis method and rare earth site magnetism. PDF analysis suggests that electronic phase separation occurs without accompanying chemical phase segregation or changes in the short-range crystallographic symmetry while synchrotron x-ray diffraction confirms that there is no change in the long-range crystallographic symmetry. X-ray absorption measurements confirm the $J_{eff}$ = 1/2 character of (Eu$_{1-x}$Ca$_{x}$)$_{2}$Ir$_{2}$O$_{7}$. Surprisingly these measurements also indicate a net electron doping, rather than the expected hole doping, indicating a compensatory mechanism. Lastly, XMCD measurements show a weak Ir magnetic polarization that is largely unaffected by Ca-doping.

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。

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