近日，美国加州大学洛杉矶分校Kogar, Anshul团队研究了一种隐藏电荷密度波液体的观测。相关论文于2025年12月30日发表在《自然—物理学》杂志上。

电荷密度波——在主体固体内部形成的电子晶体——长期以来被理论预言会融化成具有空间纹理的电子液体。尽管这种液态电荷密度波过去从未被直接观测到，但它们可能关联电子体系相图的核心特征，包括高温超导体和量子霍尔态。在有望承载液态电荷密度波的材料1T-TaS2中，结构相变阻碍了实际观测。

研究组利用飞秒光脉冲绕开这一相变限制，揭示了拓扑缺陷动力学如何调控隐藏的电荷密度波关联序。光激发后，电荷密度波衍射峰出现方位角展宽，标志着六角态的形成。在升高温度条件下，光激发会完全破坏平移序与取向序，仅留下弥散散射环——这正是液态电荷密度波的标志性特征。这些发现为缺陷解束缚相变形成电荷密度波液体提供了有力证据。更广泛而言，该方法为揭示热平衡条件下被中间相变所掩盖的电子物相开辟了新途径。

附：英文原文

Title: Observation of a hidden charge density wave liquid

Author: Lee, Joshua S. H., Sutter, Thomas M., Karapetrov, Goran, Musumeci, Pietro, Kogar, Anshul

Issue&Volume: 2025-12-30

Abstract: Charge density waves, electronic crystals that form within a host solid, have long been theorized to melt into a spatially textured electronic liquid. Although such liquid charge density waves have not been previously observed, they may be central to the phase diagrams of correlated electron systems, including high-temperature superconductors and quantum Hall states. In 1T-TaS2, a promising material for hosting a liquid charge density wave, a structural phase transition hinders observation. Here we use femtosecond light pulses to bypass this transition, revealing how topological defect dynamics govern hidden charge density wave correlations. Following photoexcitation, charge density wave diffraction peaks broaden azimuthally, indicating the emergence of a hexatic state. At elevated temperatures, photoexcitation fully destroys both translational and orientational orders, leaving only a ring of diffuse scattering—the hallmark of a liquid charge density wave. These findings offer compelling evidence for a defect-unbinding transition to a charge density wave liquid. More broadly, this approach demonstrates a route to uncover electronic phases obscured by intervening transitions in thermal equilibrium.

DOI: 10.1038/s41567-025-03108-z

Source: https://www.nature.com/articles/s41567-025-03108-z