Soft x-ray resonant scattering has been used to examine the charge and magnetic interactions in the cycloidal antiferromagnetic compound \dyfeal. By tuning to the Dy $M_4$ and $M_5$ absorption edges and the Fe L(2) and L(3) absorption edges we can directly observe the behavior of the Dy 4f and Fe 3d electron shells. Magnetic satellites surrounding the (110) Bragg peak were observed below 60 K. The diffraction peaks display a complex spectra at the Dy M(5) edge, indicative of a split 4f electron band. This is in contrast to a simple resonance observed at the Fe L(3) absorption edge, which probes the Fe 3d electron shell. Temperature dependant measurements detail the ordering of the magnetic moments on both the iron and the dysprosium antiferromagnetic cycloids. The ratio between the intensities of the Dy M(4) and M(5) remained constant throughout the temperature range, in contrast to a previous study conducted at the Dy L(2,3) edges. Our results demonstrate the ability of soft x-ray diffraction to separate the individual magnetic components in complicated multi-element magnetic structures.
A critical re-examination of resonant soft x-ray Bragg forbidden reflections in magnetite
磁铁矿，Fe $_3$ O $_4$，显示出高度复杂的低温晶体结构，可能是电荷和轨道有序的。最近的许多实验声称，这种秩序依赖于共振软X射线衍射在氧K和铁L的边缘。我们已经重新检查了这个系统，并进行了软X射线衍射实验的高品质的单晶。与文献中的先前声明相反，我们表明，在布拉格禁戒（001/2）$_c$反射处观察到的强度可以纯粹地用共振原子周围的低温结构位移解释。这并不一定意味着磁铁矿不是电荷或轨道有序的，而是目前共振软X射线实验的灵敏度不允许这种有序的结论性证明。
We use resonant soft X-ray diffraction to track the photo-induced dynamics of the antiferromagnetic structure in a NdNiO$_{3}$ thin film. Femtosecond laser pulses with a photon energy of 0.61 eV, resonant with electron transfer between long-bond and short-bond nickel sites, are used to excite the material and drive an ultrafast insulator-metal transition. Polarization sensitive soft X-ray diffraction, resonant to the nickel L$_{3}$-edge, then probes the evolution of the underlying magnetic spiral as a function of time delay with 80 picosecond time resolution. By modelling the azimuthal depende…
Resonant soft x-ray emission as a bulk probe of correlated electron behavior in metallic Sr$_x$Ca$_{1-x}$VO$_3$
采用体敏共振软X射线发射谱（RXES）、表面灵敏光电子能谱（PES）和从头算能带结构计算方法研究了Sr $_{x}$ Ca $_{1-x}$ VO $_3$中电子关联的演化.我们发现，电子相关的效果是在表面增强。强非相干哈伯德子带被发现谎言的相干准粒子的功能，在表面敏感的PES测量相比，从体积敏感的RXES的能量接近20%，和一个10%的整体带宽变窄在表面上也观察到。
The magnetic properties of rare earth compounds are usually well captured by assuming a fully localized f shell and only considering the Hund's rule ground state multiplet split by a crystal electrical field (CEF). Currently, the standard technique for probing CEF excitations in lanthanides is inelastic neutron scattering. Here we show that with the recent leap in energy resolution, resonant inelastic soft X-ray scattering has become a serious alternative for looking at CEF excitations with some distinct advantages compared to INS. As an example we study the CEF scheme in CeRh2Si2, a system th…
Superconducting transition at 38 K in insulating-overdoped La2CuO4-La1.64Sr0.36CuO4 superlattices: Evidence for interface electronic redistribution from resonant soft x-ray scattering
Samarium hexaboride (SmB$_6$), a Kondo insulator with mixed valence, has recently attracted much attention as a possible host for correlated topological surface states. Here, we use a combination of x-ray absorption and reflectometry techniques, backed up with a theoretical model for the resonant $M_{4,5}$ absorption edge of Sm and photoemission data, to establish laterally averaged chemical and valence depth profiles at the surface of SmB$_6$. We show that upon cleaving, the highly polar (001) surface of SmB$_6$ undergoes substantial chemical and valence reconstruction, resulting in boron ter…
Multiple intriguing phenomena have recently been discovered in tetragonal Heusler compounds, where $D_{2d}$ symmetry sets a unique interplay between Dzyaloshinskii-Moriya (DM) and magnetic dipolar interactions. In the prototype $D_{2d}$ compound Mn$_{1.4}$PtSn, this has allowed the stabilization of exotic spin textures such as first-reported anti-skyrmions or elliptic Bloch-type skyrmions. While less attention has so far been given to the low-field spiral state, this remains extremely interesting as a simplest phase scenario on which to investigate the complex hierarchy of magnetic interaction…
The frustrated magnet has been regarded as a system that could be a promising host material for the quantum spin liquid (QSL). However, it is difficult to determine the spin configuration and the corresponding mechanism in this system, because of its geometrical frustration (i.e., crystal structure and symmetry). Herein, we systematically investigate one of the geometrically frustrated magnets, the TbB$_{4}$ compound. Using resonant soft x-ray scattering (RSXS), we explored its spin configuration, as well as Tb's quadrupole. Comprehensive evaluations of the temperature and photon energy / pola…
Electronic phase transitions in Pr$_{0.5}$Ca$_{0.5}$MnO$_3$ epitaxial thin films revealed by resonant soft x-ray scattering
研究了在（LaAl O $_3$）$_{0.3}$ -（SrAl $_{0.5}$ Ta $_{0.5}$ O $_3$）$_{0.7}$（LSAT）（011）$_c$上生长的Pr $_{0.5}$ Ca $_{0.5}$ MnO $_3$外延薄膜的磁性和轨道有序.在一个新的实验方法中，极化和能量依赖性的共振软X射线散射被用来揭示显着修改的磁序在膜相比，散装，即（i）不同的磁有序波矢量，（ii）不同的磁易轴和（iii）在低温下的额外的磁重排过渡。这些观察结果表明，强烈的影响的外延应变的自旋顺序，这是介导的轨道自由度，并提供了一个有前途的路线，以调整磁性能的锰氧化物薄膜。我们的研究结果进一步表明，共振软X射线散射是一个非常合适的技术来研究磁性的薄膜，中子散射不能很容易地应用于由于小的样品体积。
Identifying what broken symmetries are present in the cuprates has become a major area of research. Many authors have reported evidence for so-called "$Q \sim 0$" order that involves broken inversion, mirror, chiral, or time-reversal symmetry that is uniform in space. Not all these observations are well understood and new experimental probes are needed. Here we use resonant soft x-ray scattering (RSXS) to search for $Q \sim 0$ order in Bi$_{2.1}$Sr$_{1.9}$CaCu$_2$O$_{8+x}$ (Bi-2212) by measuring the region of a forbidden Bragg peak, $(0,0,3)$, which is normally extinguished by symmetry but may…
The relationship between the magnetic interaction and photoinduced dynamics in antiferromagnetic perovskites is investigated in this study. In La${}_{1/3}$Sr${}_{2/3}$FeO${}_{3}$ thin films, commensurate spin ordering is accompanied by charge disproportionation, whereas SrFeO${}_{3}$ thin films show incommensurate helical antiferromagnetic spin ordering due to increased ferromagnetic coupling compared to La${}_{1/3}$Sr${}_{2/3}$FeO${}_{3}$. To understand the photoinduced spin dynamics in these materials, we investigate the spin ordering through time-resolved resonant soft X-ray scattering. In …
Resonant elastic X-ray scattering has been widely employed for exploring complex electronic ordering phenomena, like charge, spin, and orbital order, in particular in strongly correlated electronic systems. In addition, recent developments of pump-probe X-ray scattering allow us to expand the investigation of the temporal dynamics of such orders. Here, we introduce a new time-resolved Resonant Soft X-ray Scattering (tr-RSXS) endstation developed at the Pohang Accelerator Laboratory X-ray Free Electron Laser (PAL-XFEL). This endstation has an optical laser (wavelength of 800 nm plus harmonics) …
Resonant soft x-ray scattering (RSXS) is a leading probe of valence band order in materials best known for detecting charge density wave order in the copper-oxide superconductors. One of the biggest limitations on the RSXS technique is the presence of a severe fluorescence background which, like the RSXS cross section itself, is enhanced under resonant conditions. This background prevents the study of weak signals such as diffuse scattering from glassy or fluctuating order that is spread widely over momentum space. Recent advances in superconducting transition edge sensor (TES) detectors have …
Effect of core-valence intra-atomic quadrupolar interaction in resonant x-ray scattering at the Dy M$_{4,5}$ edges in DyB$_2$C$_2$
采用考虑晶场效应的原子多重态哈密顿量，并在3d核与4f价壳层之间引入原子内四极相互作用，计算了DyB $_2$ C $_2$中$(00{1/2})$在Dy M $_{4,5}$边的共振软X射线Bragg衍射强度与能量的关系.将这些计算与实验结果（Mulders等人，J.物理学：康登斯Matter 18（2006）11195）在DyB $_2$ C $_2$的反铁四极和反铁磁相中。我们再现所有的功能出现$(00{1/2})$反射能量分布在反铁四极有序相，我们再现的行为的共振X射线散射强度在不同的能量附近的Dy M $_5$边缘时，温度降低反铁磁相。
Motivated by the ongoing effort to search for high-resolution signatures of quantum spin liquids, we investigate the temperature dependence of the indirect resonant inelastic x-ray scattering (RIXS) response for the Kitaev honeycomb model. We find that, as a result of spin fractionalization, the RIXS response changes qualitatively at two well-separated temperature scales, $T_L$ and $T_H$, which correspond to the characteristic energies of the two kinds of fractionalized excitations, $\mathbb{Z}_2$ gauge fluxes and Majorana fermions, respectively. While thermally excited $\mathbb{Z}_2$ gauge fl…
We report an Fe $L$-edge resonant inelastic x-ray scattering (RIXS) study of the unusual superconductor $β$-FeSe. The high energy resolution of this RIXS experiment ($\approx\,$55$\,$meV FWHM) made it possible to resolve low-energy excitations of the Fe $3d$ manifold. These include a broad peak which shows dispersive trends between 100-200$\,$meV along the $(π,0)$ and $(π,π)$ directions of the one-Fe square reciprocal lattice, and which can be attributed to paramagnon excitations. The multi-band valence state of FeSe is among the most metallic in which such excitations have been discerned by s…
