Giant X-ray circular dichroism in a time-reversal invariant altermagnet
| Autor: | Okamoto, Jun, Wang, Ru-Pan, Chu, Yen-Yi, Shiu, Hung-Wei, Singh, Amol, Huang, Hsiao-Yu, Mou, Chung-Yu, Teh, Sucitto, Jeng, Horng-Tay, Du, Kai, Xu, Xianghan, Cheong, Sang-Wook, Du, Chao-Hung, Chen, Chien-Te, Fujimori, Atsushi, Huang, Di-Jing |
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| Rok vydání: | 2023 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| Popis: | X-ray circular dichroism, arising from the contrast in X-ray absorption between opposite photon helicities, serves as a spectroscopic tool to measure the magnetization of ferromagnetic materials and identify the handedness of chiral crystals. Antiferromagnets with crystallographic chirality typically lack X-ray magnetic circular dichroism because of time-reversal symmetry, yet exhibit weak X-ray natural circular dichroism. Here, we report the observation of giant natural circular dichroism in the Ni $L_3$-edge X-ray absorption of Ni$_3$TeO$_6$, a polar and chiral antiferromagnet with effective time-reversal symmetry. To unravel this intriguing phenomenon, we propose a phenomenological model that classifies the movement of photons in a chiral crystal within the same symmetry class as that of a magnetic field. The coupling of X-ray polarization with the induced magnetization yields giant X-ray natural circular dichroism, revealing the altermagnetism of Ni$_3$TeO$_6$. Our findings provide evidence for the interplay between magnetism and crystal chirality in natural optical activity. Additionally, we establish the first example of a new class of magnetic materials exhibiting circular dichroism with time-reversal symmetry. Comment: Accepted by Advanced Materials (2024.2.16) Revised title: Giant X-ray circular dichroism in a time-reversal invariant altermagnet Revised drafts: Main 14 pages, 4 figures, and SI 20 pages, 8 figures |
| Databáze: | arXiv |
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