标题： 手性电荷密度波的预测性第一性原理框架 显示英文标题

标题： A Predictive First-Principles Framework of Chiral Charge Density Waves

摘要： 实现和调节手性在物理学、化学和材料科学中是基础性的。手性电荷密度波（CDW），其中手性来源于关联的电荷序，由于其奇特的输运和光学性质而受到广泛关注。然而，缺乏一个预测手性CDW材料的通用框架，主要是因为其基本机制仍不明确。在此，我们通过开发第一个全面的预测框架来解决这一挑战，系统地通过第一性原理计算识别手性CDW材料。关键在于之前被忽视的层间CDW Q矢量的相位差，这与不同层之间的相反集体原子位移有关。这种相位差导致Q矢量的螺旋排列，最终在实空间中产生手性结构。我们通过将该框架应用于kagome晶格AV$_{3}$Sb$_{5}$ (A = K, Rb, Cs)，成功预测了出现的结构手性。为了展示我们方法的普遍性，我们将它扩展到预测三角晶格NbSe$_{2}$中的手性CDW。除了材料预测外，我们的理论揭示了手性CDW材料中一种普遍且前所未有的霍尔效应，这种效应在没有外部磁场或固有磁化的情况下发生。我们在CsV$_{3}$Sb$_{5}$上的实验验证了这一预测，观察到一个独特的特征，即当输入电流反转时，霍尔电导率的符号会发生反转，这是一种不同于已知霍尔效应的现象。我们的研究结果阐明了手性CDW的机制，并为发现具有非常规量子特性的材料开辟了新途径，有望应用于下一代电子和自旋电子器件。 显示英文摘要

摘要： Implementing and tuning chirality is fundamental in physics, chemistry, and material science. Chiral charge density waves (CDWs), where chirality arises from correlated charge orders, are attracting intense interest due to their exotic transport and optical properties. However, a general framework for predicting chiral CDW materials is lacking, primarily because the underlying mechanisms remain elusive. Here, we address this challenge by developing the first comprehensive predictive framework, systematically identifying chiral CDW materials via first-principles calculations. The key lies in the previously overlooked phase difference of the CDW Q-vectors between layers, which is linked to opposite collective atomic displacements across different layers. This phase difference induces a spiral arrangement of the Q-vectors, ultimately giving rise to a chiral structure in real space. We validate our framework by applying it to the kagome lattice AV$_{3}$Sb$_{5}$ (A = K, Rb, Cs), successfully predicting emergent structural chirality. To demonstrate the generality of our approach, we extend it to predict chiral CDWs in the triangular-lattice NbSe$_{2}$. Beyond material predictions, our theory uncovers a universal and unprecedented Hall effect in chiral CDW materials, occurring without external magnetic fields or intrinsic magnetization. Our experiments on CsV$_{3}$Sb$_{5}$ confirm this prediction, observing a unique signature where the Hall conductivity's sign reverses when the input current is reversed, a phenomenon distinct from known Hall effects. Our findings elucidate the mechanisms behind chiral CDWs and open new avenues for discovering materials with unconventional quantum properties, with potential applications in next-generation electronic and spintronic devices.