Division of Materials Physics, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan.
RIKEN SPring-8 Center, Sayo, Hyogo 679-5148, Japan.
Nat Mater. 2014 Jun;13(6):611-8. doi: 10.1038/nmat3942. Epub 2014 Apr 6.
Resonant X-ray diffraction (RXD) uses X-rays in the vicinity of a specific atomic absorption edge and is a powerful technique for studying symmetry breaking by motifs of various multipole moments, such as electric monopoles (charge), magnetic dipoles (spin) and electric quadrupoles (orbital). Using circularly polarized X-rays, this technique has been developed to verify symmetry breaking effects arising from chirality, the asymmetry of an object upon its mirroring. Chirality plays a crucial role in the emergence of functionalities such as optical rotatory power and multiferroicity. Here we apply spatially resolved RXD to reveal the helix chirality of Dy 4f electric quadrupole orientations and its domain structure in DyFe3(BO3)4, which shows a reversible phase transition into an enantiomorphic space-group pair. The present study provides evidence for a helix chiral motif of quadrupole moments developed in crystallographic helix chirality.
共振 X 射线衍射（RXD）使用特定原子吸收边缘附近的 X 射线，是研究各种多极矩图案引起的对称性破缺的强大技术，例如电单极子（电荷）、磁偶极子（自旋）和电四极子（轨道）。该技术使用圆偏振 X 射线发展而来，用于验证手性引起的对称性破缺效应，手性是物体在镜像时的不对称性。手性在出现旋光性和多铁性等功能方面起着至关重要的作用。在这里，我们应用空间分辨 RXD 来揭示 DyFe3(BO3)4 中 Dy 4f 电四极子取向的螺旋手性及其畴结构，该结构显示出可逆的相转变为对映体空间群对。本研究为晶体学螺旋手性中开发的四极矩螺旋手性图案提供了证据。
