过渡金属二硫族化物因其广泛存在超导、电荷密度波等新奇的物理现象成为了近些年来凝聚态物理研
究中的一大热点, 同时这也为研究超导和电荷密度波等电子序之间的相互作用提供了典型的材料体系. 本文
利用角分辨光电子能谱对1T 结构的NbSeTe 单晶进行系统的研究, 揭示了其电子结构. 沿高对称方向的能带
测量发现, 1T-NbSeTe 布里渊区M 点附近存在一个范霍夫奇点, 能量位于费米能以下约250 meV 处. 对能带
色散的仔细分析发现该体系中没有明显电子-玻色子(声子) 耦合带来的能带扭折. 基于上述实验结果, 对过
渡金属二硫族化物中电荷密度波和超导的产生以及1T-NbSeTe 中电荷密度波和超导被抑制的可能原因进行
了讨论.

Transition metal dichalcogenides (TMDs) have attracted a lot of interest in condensed matter physics research due to the existence of multiple novel physical phenomena, including superconductivity and charge density wave order, and also TMDs provide a unique window for studying the interactions between different ground states. In this work, the electronic structure of 1T-NbSeTe is systematically examined by angle-resolved photoemission spectroscopy (ARPES) for the first time. A van Hove singularity (VHS) is identified at the M point, with binding energy of 250 meV below the Fermi level. Careful analysis is carried out to examine the band dispersions along different high symmetry directions and the possible many-body effect. However, the dispersion kink —a characteristic feature of electron-boson coupling is not obvious in this system. In TMD materials, the van Hove singularity near the Fermi level and the electron-boson (phonon) coupling are suggested to play an important role in forming charge density wave (CDW) and superconductivity, respectively. In this sense, our experimental results may provide a direct explanation for the weakened CDW and relatively low superconducting transition temperature in 1T-NbSeTe. These results may also provide an insight into the charge-density-wave orders in the relevant material systems.