论文标题
结构扭曲对T型过渡金属二分法源的电子结构的影响
Effects of Structural Distortions on the Electronic Structure of T-type Transition Metal Dichalcogenides
论文作者
论文摘要
单层过渡金属二分裂基化（TMDC）可以采用与金属原子不同配位相对应的两个不同的结构。 TMDCs adopting the T-type structure exhibit a rich and diverse set of phenomena, including charge density waves (CDW) in a $\sqrt{13}\times\sqrt{13}$ supercell pattern in TaS$_2$ and TaSe$_2$, and a possible excitonic insulating phase in TiSe$_2$.这些属性使T-TMDC的层次异质结构设备的理想组件。为了预测不同分层材料组合的新兴特性，一个人需要简单，准确的模型，以考虑晶格不匹配，放松，应变和结构变形的潜在影响。先前的研究已经开发了用于H型TMDC [ARXIV：1709.07510]的从头开始结合的哈密顿量。在这里，我们将这项工作扩展到包括T型TMDC。我们使用三个示例系统演示了模型的功能：一维正弦波，tise $ _2 $中的2 $ \ times $ 2 cdw和$ \ sqrt {13} \ times \ times \ sqrt {13} $ cdw in tas $ _2 $。使用带的技术展开的技术，我们将扭曲晶体的电子结构与原始带的结构进行比较，并与直接DFT计算找到了极好的一致性，前提是扭曲的幅度仍然保持在线性状态。
Single-layer transition metal dichalcogenides (TMDCs) can adopt two distinct structures corresponding to different coordination of the metal atoms. TMDCs adopting the T-type structure exhibit a rich and diverse set of phenomena, including charge density waves (CDW) in a $\sqrt{13}\times\sqrt{13}$ supercell pattern in TaS$_2$ and TaSe$_2$, and a possible excitonic insulating phase in TiSe$_2$. These properties make the T-TMDCs desirable components of layered heterostructure devices. In order to predict the emergent properties of combinations of different layered materials, one needs simple and accurate models for the constituent layers which can take into account potential effects of lattice mismatch, relaxation, strain, and structural distortion. Previous studies have developed ab initio tight-binding Hamiltonians for H-type TMDCs [arXiv:1709.07510]. Here we extend this work to include T-type TMDCs. We demonstrate the capabilities of our model using three example systems: a 1-dimensional sinusoidal ripple, the 2$\times$2 CDW in TiSe$_2$, and the $\sqrt{13}\times\sqrt{13}$ CDW in TaS$_2$. Using the technique of band unfolding we compare the electronic structure of the distorted crystals to the pristine band structure and find excellent agreement with direct DFT calculations, provided the magnitude of the distortions remains in the linear regime.
