标题： X射线发射光谱偏振测量用于强各向异性单晶系统的行罗兰圆几何方法 显示英文标题

标题： X-ray Emission Spectropolarimetry of Strongly Anisotropic Single Crystal Systems using a Rowland Circle Geometry

摘要： 偏振依赖性在X射线光谱学中历来被广泛用于确定磁性和局部几何特性，但更广泛地作为提高对单个磁性轨道电子结构敏感度的一种方法。这通常是在X射线吸收的背景下通过诸如X射线磁圆二色性或X射线线性二色性等技术实现的，但在X射线发射中的应用却很少。在这里，我们探讨了在核心到核心（CtC）和价带到核心发射（VtC）线中，两种3d过渡金属系统的偏振发射所包含的信息。我们展示了如何利用Rowland圆几何结构作为光谱偏振计，并将其应用于LiVCuO4和DyNiC2中自旋-1/2 Cu(II)和自旋-0 Ni(II)离子的X射线发射光谱学。从这里，我们探讨了偏振XES如何在价带水平上探测占据态密度，要么通过库仑交换（CtC X射线发射）的二级效应，要么通过直接跃迁（VtC X射线发射）。我们发现，偏振X射线发射可以提供关于价带电子轨道占据情况的见解，这与偏振吸收或角度分辨光电发射光谱技术所能实现的效果类似。最后，我们强调了如何从一组线性独立的定向发射光谱中提取单独偏振的偶极发射光谱，从而在高布拉格角下进行偏振测量，并减少实验展宽。 显示英文摘要

摘要： Polarization dependence has historically seen extensive use in x-ray spectroscopy to determine magnetic and local geometric properties, but more broadly as a way to gain extra sensitivity to electronic structure at the level of individual magnetic orbitals. This is often done in the context of x-ray absorption through techniques like x-ray magnetic circular dichroism or x-ray linear dichroism, but it has seen little application to x-ray emission. Here we explore the information contained in the polarized emission of two 3d transition metal systems across both core-to-core (CtC) and valence-to-core emission (VtC) lines. We demonstrate how the Rowland circle geometry can be used as a spectropolarimeter, and apply it to the x-ray emission spectroscopy of spin-1/2 Cu(II) and spin-0 Ni(II) ions in LiVCuO4 and DyNiC2, respectively. From this we explore how the polarized XES interrogates of the occupied density of states at the valence level, either as a second order effect through Coulomb exchange (CtC x-ray emission) or by direct transitions (VtC x-ray emission). We find that the polarized x-ray emission can provide insights into the valence electron orbital occupation, in much the same way that is achievable with polarized absorption or angle-resolved photoemission spectroscopy techniques. Finally, we highlight how the individually polarized dipole emission spectra can be extracted from a linearly independent suite of directed emission spectra, allowing for polarized measurements at high Bragg angle with lower experimental broadening.