近日，美国波士顿学院Burch, Kenneth S.团队研究了稀土三碲化物中缠绕电荷和轨道序的铁轴密度波。该研究于2025年9月1日发表在《自然—物理学》杂志上。
轴向振幅模式——通常被称为希格斯模式——在电荷密度波系统中的发现，如稀土三碲化物，表明了一个隐藏秩序的存在。一项理论研究提出，这种轴向希格斯模式是由电荷密度波的隐藏轨道结构产生的，它产生了铁轴电荷序。然而，具体隐藏序的实验证据一直缺乏。
研究组证明了整个稀土三碲化物的铁轴电子起源顺序。在ErTe3和HoTe3中，在不同的有序温度下表现出两种不同的电荷密度波，详细的研究表明，高温电荷有序相打破了平移，旋转和所有垂直以及对角镜像对称。此外，这个相位产生了一个轴向希格斯模和一个轴向电子隙。相比之下，低温相只打破了平移对称，并产生标量希格斯模。值得注意的是，两个相位都保持了空间反转和时间反转的对称性。这些发现与轨道和电荷序耦合驱动的铁轴相位一致，突出了希格斯模式在揭示相互交织的电荷密度波系统中的隐藏顺序方面的作用。
附：英文原文
Title: Ferroaxial density wave from intertwined charge and orbital order in rare-earth tritellurides
Author: Singh, Birender, McNamara, Grant, Kim, Kyung-Mo, Siddique, Saif, Funni, Stephen D., Zhang, Weizhe, Luo, Xiangpeng, Sakrikar, Piyush, Kenney, Eric M., Singha, Ratnadwip, Alekseev, Sergey, Ghorashi, Sayed Ali Akbar, Hicken, Thomas J., Baines, Christopher, Luetkens, Hubertus, Wang, Yiping, Plisson, Vincent M., Geiwitz, Michael, Occhialini, Connor A., Comin, Riccardo, Graf, Michael J., Zhao, Liuyan, Cano, Jennifer, Fernandes, Rafael M., Cha, Judy J., Schoop, Leslie M., Burch, Kenneth S.
Issue&Volume: 2025-09-01
Abstract: The discovery of the axial amplitude mode—commonly referred to as the Higgs mode—in charge density wave systems, such as rare-earth tritellurides, indicates the presence of a hidden order. A theoretical study proposed that this axial Higgs mode arises from a hidden orbital texture of the charge density wave, which produces a ferroaxial charge order. However, experimental evidence for the specific hidden order has been lacking. Here, we demonstrate a ferroaxial order of electronic origin throughout the rare-earth tritellurides. In ErTe3 and HoTe3, which exhibit two distinct charge density waves with different ordering temperatures, a detailed investigation shows that the high-temperature charge order phase breaks translational, rotational and all vertical as well as diagonal mirror symmetries. Furthermore, this phase produces an axial Higgs mode and an axial electronic gap. By contrast, the low-temperature phase breaks only translational symmetry and gives rise to a scalar Higgs mode. Notably, both phases preserve the space inversion and time-reversal symmetries. These findings are consistent with a ferroaxial phase driven by coupled orbital and charge orders, highlighting the role of Higgs modes in revealing hidden orders in systems with intertwined charge density waves.
DOI: 10.1038/s41567-025-03008-2
Source: https://www.nature.com/articles/s41567-025-03008-2