本项目聚焦具有丰富物理特性的金属性第五副族二硫族化合物（NbX2和TaX2，X＝S、Se）的制备和物性研究，预期通过化学气相沉积方法可控制备NbX2和TaX2的单层和少层材料，然后利用变温拉曼光谱和变温电学测量研究其电荷密度波特性和超导特性。由于超导材料的库珀对结合能以及电荷密度波的激发能都很低（与NbX2和TaX2中层层相互作用可比拟），预期NbX2和TaX2的相变温度（Tc和TCDW）与材料的层数、层层堆垛方式紧密相关。本项目将揭示NbX2和TaX2的Tc和TCDW随材料的层数、层层堆垛的变化规律，该规律能为NbX2和TaX2的物性调控提供坚实基础。

This project focuses on the synthesis and property investigation of group VB transition metal dichalcogenides which have rich physical properties. In details, chemical vapor deposition (CVD) will be used for controllable synthesis of NbX2 and TaX2 (X=S、Se) monolayers and few-layers. And then temperature-dependent Raman spectroscopy and electrical measurements will be conducted to investigate the charge wave density (CDW) and superconductivity. Since the binding energy of copper pairs and CDW excitation energy in NbX2 and TaX2 are low (~meV) and comparable to the layer-layer interactions, it is expected that the phase transition temperature Tc and TCDW are sensitive to the layer number and the layer-layer stacking in NbX2 and TaX2. This project will reveal the dependence of Tc and TCDW on layer number and layer-layer stacking of NbX2 and TaX2, which will gain fundamental knowledge for further property engineering of NbX2 and TaX2.