Abstract
X-ray beams with orbital angular momentum (OAM) are a promising tool for x-ray characterization techniques. Beams with OAM have a helicity - an azimuthally varying phase - which leads to a gradient of the light field. New material properties can be probed by utilizing the helicity of an OAM beam. Here, we demonstrate a dichroic effect in resonant diffraction from an artificial antiferromagnet with a topological defect. We found that the scattered OAM beam has circular dichroism at the antiferromagnetic Bragg peak whose sign is coupled to its helicity, which reveals the real-space configuration of the antiferromagnetic ground state. Thermal cycling of the artificial antiferromagnet can change the ground state, as indicated by reversal of the sign of circular dichroism. This result is one of the first demonstrations of a soft x-ray spectroscopy characterization technique utilizing the OAM of x rays. This helicity-dependent circular dichroism exemplifies the potential to utilize OAM beams to probe matter in a way that is inaccessible using currently available x-ray techniques.
| Original language | English |
|---|---|
| Article number | L060407 |
| Journal | Physical Review B |
| Volume | 107 |
| Issue number | 6 |
| DOIs | |
| State | Published - Feb 1 2023 |
Bibliographical note
Publisher Copyright:© 2023 American Physical Society.
Funding
This work was supported by the Laboratory Directed Research and Development Program of Lawrence Berkeley National Laboratory under U.S. Department of Energy Contract No. DE-AC02-05CH11231. This work used the Timepix-based soft x-ray detector, development of which is supported by DOE through award RoyTimepixDetector. This research used resources of the Advanced Light Source, a U.S. DOE Office of Science User Facility under Contract No. DE-AC02-05CH11231. Work at the Molecular Foundry was supported by the Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. Work performed at the Center for Nanoscale Materials, a U.S. Department of Energy Office of Science User Facility, was supported by the U.S. DOE, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. The work is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Award No. DE-SC0016519. This work was performed in part at the University of Kentucky Center for Nanoscale Science and Engineering, Electron Microscopy Center, and Center for Advanced Materials, members of the National Nanotechnology Coordinated Infrastructure (NNCI), which is supported by the National Science Foundation (Grant No. NNCI-2025075).
| Funders | Funder number |
|---|---|
| DOE Basic Energy Sciences | |
| Laboratory Directed Research and Development | |
| Office of Science Programs | |
| Center for Advanced Meta-Materials | |
| U.S. Department of Energy EPSCoR | DE-AC02-05CH11231, DE-AC02-06CH11357, DE-SC0016519 |
| National Science Foundation Arctic Social Science Program | 2025075 |
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics