论文标题
电子 - 音波耦合在过渡金属二分法中对声子和电子不稳定性的决定性作用
Decisive role of electron-phonon coupling for phonon and electron instabilities in transition metal dichalcogenides
论文作者
论文摘要
过渡金属二分法中的电荷密度波（CDW）的起源一直处于热门辩论中，尚未达成结论性的一致性。在这里，我们提出了一个AB-Initio框架，以准确描述费米表面嵌套和电子偶联（EPC），并系统地研究它们在CDW形成中的作用。使用单层1H-NBSE $ _2 $和1T-VTE $ _2 $作为代表性示例，我们表明，这是动量依赖的EPC柔和的声子频率，在CDW矢量（指示CDW形成）中会变成想象中的（声子Inmistibility）。此外，只有在平均场模型中包含EPC时，才能正确预测CDW间隙开口（电子不稳定性）的分布。这些结果强调了EPC在CDW形成中的决定性作用。我们的分析过程是一般的，可以应用于其他CDW系统。
The origin of the charge density wave (CDW) in transition metal dichalcognides has been in hot debate and no conclusive agreement has been reached. Here, we propose an ab-initio framework for an accurate description of both Fermi surface nesting and electron-phonon coupling (EPC) and systematically investigate their roles in the formation of CDW. Using monolayer 1H-NbSe$_2$ and 1T-VTe$_2$ as representative examples, we show that it is the momentum-dependent EPC softens the phonon frequencies, which become imaginary (phonon instabilities) at CDW vectors (indicating CDW formation). Besides, the distribution of the CDW gap opening (electron instabilities) can be correctly predicted only if EPC is included in the mean-field model. These results emphasize the decisive role of EPC in the CDW formation. Our analytical process is general and can be applied to other CDW systems.
