发表机构
Universidade Federal de Mato Grosso; Norwegian University of Science and Technology (NTNU); University of Brasília（马托格罗索联邦大学; 挪威科技大学; 巴西利亚大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究结合cRPA和DFT+DMFT，构建单层1H-NbS2的有效单带模型，准确再现低能谱和Van Hove奇点，证明局域相互作用足以描述其强关联金属行为。
AI 中文摘要
单层$1\mathrm{H}\text{-}\mathrm{NbS}_2$承载一个以Nb-$d_{z^2}$轨道为主要特征的分离良好的金属带，为在单带体系中探测电子关联提供了理想平台。在本工作中，我们通过结合第一性原理Wannier插值、约束随机相位近似（cRPA）和DFT+DMFT，对$1\mathrm{H}\text{-}\mathrm{NbS}_2$进行了全面研究。我们表明，一个有效的单带模型能够准确捕捉低能电子结构，重现ARPES和STS $dI/dV$谱中的关键实验特征，包括特征性的Van Hove奇点。虽然静态DFT+$U$无法描述该体系的关联金属性质，但DFT+DMFT成功解释了谱权重再分布和动态关联。通过直接在孤立的Nb-$d_{z^2}$带内定义cRPA目标子空间，我们获得了重整化的局域相互作用$U_{\mathrm{cRPA}} = 1.138~\mathrm{eV}$。该相互作用稳定了一个强关联金属态，该金属态在冷却时保持稳健。值得注意的是，这个最小单带模型捕捉到的谱展宽与先前在更精细处理中报道的相似——这些处理包含更大的局域相互作用（$U \sim 1.8~\mathrm{eV}$，源自多轨道cRPA构造）、格点间库仑项（$V$）和电子-声子耦合——表明仅一个一致降维的局域相互作用就能捕捉单层$1\mathrm{H}\text{-}\mathrm{NbS}_2$实验观测到的低能行为的关键方面。
英文摘要
Monolayer $1\mathrm{H}\text{-}\mathrm{NbS}_2$ hosts a well-separated metallic band of predominant Nb-$d_{z^2}$ character, providing an ideal platform to probe electronic correlations within a single-band setting. In this work, we present a comprehensive study of $1\mathrm{H}\text{-}\mathrm{NbS}_2$ by combining first-principles Wannier interpolation, constrained random-phase approximation (cRPA), and DFT+DMFT. We show that an effective single-band model accurately captures the low-energy electronic structure, reproducing key experimental features from ARPES and STS $dI/dV$ spectra, including a characteristic Van Hove singularity. While static DFT+$U$ fails to describe the correlated metallic nature of the system, DFT+DMFT successfully accounts for the spectral weight redistribution and dynamic correlations. By defining the cRPA target subspace directly within the isolated Nb-$d_{z^2}$ band, we obtain a renormalized local interaction of $U_{\mathrm{cRPA}} = 1.138~\mathrm{eV}$. This interaction stabilizes a strongly correlated metallic state that remains robust upon cooling. Remarkably, this minimal single-band model captures a spectral broadening similar to that previously reported in more elaborate treatments - incorporating larger local interactions ($U \sim 1.8~\mathrm{eV}$, derived from a multiorbital cRPA construction), intersite Coulomb terms ($V$), and electron-phonon coupling - demonstrating that a consistently downfolded local interaction alone can already capture key aspects of the experimentally observed low-energy behavior of monolayer $1\mathrm{H}\text{-}\mathrm{NbS}_2$.
Comments12 pages
