Rutile RuO2 has been posited as a potential d-wave altermagnetism candidate, with a predicted significant spin splitting up to 1.4 eV. Despite accumulating theoretical predictions and transport measurements, direct spectroscopic observation of spin splitting has remained elusive. Here, we employ spin- and angle-resolved photoemission spectroscopy to investigate the band structures and spin polarization of thin-film and single-crystal RuO2. Contrary to expectations of altermagnetism, our analysis indicates that RuO2's electronic structure aligns with those predicted under non-magnetic conditions, exhibiting no evidence of the hypothesized spin splitting. Additionally, we observe significant in-plane spin polarization of the low-lying bulk bands, which is antisymmetric about the high-symmetry plane and contrary to the d-wave spin texture due to time-reversal symmetry breaking in altermagnetism. These findings definitively challenge the altermagnetic order previously proposed for rutile RuO2, prompting a reevaluation of its magnetic properties.
@article{arxiv.2409.13504,
title = {Absence of altermagnetic spin splitting character in rutile oxide RuO$_2$},
author = {Jiayu Liu and Jie Zhan and Tongrui Li and Jishan Liu and Shufan Cheng and Yuming Shi and Liwei Deng and Meng Zhang and Chihao Li and Jianyang Ding and Qi Jiang and Mao Ye and Zhengtai Liu and Zhicheng Jiang and Siyu Wang and Qian Li and Yanwu Xie and Yilin Wang and Shan Qiao and Jinsheng Wen and Yan Sun and Dawei Shen},
journal= {arXiv preprint arXiv:2409.13504},
year = {2024}
}
Comments
7 pages, 4 figures. Published in Physical Review Letters