近日，美国密歇根大学的Liuyan Zhao及其研究小组与美国德克萨斯理工大学的Rui He等人合作并取得一项新进展。经过不懈努力，他们揭示蜂窝范德华磁体中从三维反铁磁体到二维残余向列态的维数交叉。相关研究成果已于2024年8月26日在国际知名学术期刊《自然—物理学》上发表。
该研究团队展示了从三维体材料中的之字形反铁磁有序到二维几层范德华磁体NiPS3样品中的Z3残余波茨向列相的转变。自旋弛豫测量和光学光谱测量表明，随着NiPS3层数的减少，自旋波动在吉赫兹到太赫兹范围内得到增强。
蒙特卡洛模拟证实了实验中观察到的三倍旋转对称性破缺，但表明在NiPS3的薄层中平移对称性得到了恢复。因此，这项研究结果表明，强烈的量子波动在破坏更常规磁相之后，可以稳定一种非常规的磁相。
据悉，在低维度下显著增强的波动和无序效应，在产生非平凡物质相（如由复合序参量表征的残余有序相）方面可能发挥至关重要的作用。然而，低维度下由波动驱动的磁性相仍然相对未被探索。
附：英文原文
Title: Dimensionality crossover to a two-dimensional vestigial nematic state from a three-dimensional antiferromagnet in a honeycomb van der Waals magnet
Author: Sun, Zeliang, Ye, Gaihua, Zhou, Chengkang, Huang, Mengqi, Huang, Nan, Xu, Xilong, Li, Qiuyang, Zheng, Guoxin, Ye, Zhipeng, Nnokwe, Cynthia, Li, Lu, Deng, Hui, Yang, Li, Mandrus, David, Meng, Zi Yang, Sun, Kai, Du, Chunhui Rita, He, Rui, Zhao, Liuyan
Issue&Volume: 2024-08-26
Abstract: The effects of fluctuations and disorder, which are substantially enhanced in reduced dimensionalities, can play a crucial role in producing non-trivial phases of matter such as vestigial orders characterized by a composite order parameter. However, fluctuation-driven magnetic phases in low dimensions have remained relatively unexplored. Here we demonstrate a phase transition from the zigzag antiferromagnetic order in the three-dimensional bulk to a Z3 vestigial Potts nematicity in two-dimensional few-layer samples of van der Waals magnet NiPS3. Our spin relaxometry and optical spectroscopy measurements reveal that the spin fluctuations are enhanced over the gigahertz to terahertz range as the layer number of NiPS3 reduces. Monte Carlo simulations corroborate the experimental finding of threefold rotational symmetry breaking but show that the translational symmetry is restored in thin layers of NiPS3. Therefore, our results show that strong quantum fluctuations can stabilize an unconventional magnetic phase after destroying a more conventional one.
DOI: 10.1038/s41567-024-02618-6
Source: https://www.nature.com/articles/s41567-024-02618-6