发表机构
Imperial College London（帝国理工学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
通过第一性原理计算，发现扭转NbSe2/MoSe2双层中邻近效应可在MoSe2层诱导出非均匀的电荷密度波，主导机制为层间Se原子空间位阻排斥，且强度敏感于层间距离。
AI 中文摘要
二维材料的扭转异质双层已成为研究新兴物质相的平台。在本工作中，我们利用第一性原理计算研究了扭转NbSe$_2$/MoSe$_2$双层中的电荷密度波（CDW）。我们观察到两层中都形成了CDW，尽管MoSe$_2$在其单层形式中并不具有CDW。此外，我们发现CDW高度不均匀，在两层各自的莫尔晶胞中，填充中心、空心中心和六角形CDW共存。我们评估了MoSe$_2$层中CDW形成的不同机制，并得出结论，主导机制是范德华间隙两侧Se原子之间的空间位阻排斥。这种效应的强度对层间距离高度敏感，这解释了为什么MoSe$_2$层中的CDW振幅强烈依赖于局部堆叠排列。我们的工作表明，通过邻近效应可以在扭转异质双层中诱导出新的破缺对称性相。
英文摘要
Twisted heterobilayers of two-dimensional materials have emerged as a platform for studying emergent phases of matter. In this work, we investigate charge density waves (CDW) in a twisted NbSe$_2$/MoSe$_2$ bilayer using first-principles calculations. We observe CDW formation in both layers, even though MoSe$_2$ does not feature a CDW in its monolayer form. Moreover, we find that the CDW is highly non-uniform with filled-center, hollow-center and hexagonal CDWs coexisting in the moiré unit cells of both layers. We assess different mechanisms of CDW formation in the MoSe$_2$ layer and conclude that the dominant one is the steric repulsion between Se atoms across the van der Waals gap. The strength of this effect is highly sensitive to the interlayer separation, which explains why the CDW amplitude in the MoSe$_2$ layer depends strongly on the local stacking arrangement. Our work demonstrates that novel broken-symmetry phases can be induced in twisted heterobilayers through proximity effects.
