1T-NbSeTe电子结构的角分辨光电子能谱  

Angle-resolved photoemission spectroscopy of electronic structure of 1T-NbSeTe

作　　者：魏志远 胡勇[1,2] 曾令勇 李泽宇 乔振华 罗惠霞[3] 何俊峰 Wei Zhi-Yuan;Hu Yong;Zeng Ling-Yong;Li Ze-Yu;Qiao Zhen-Hua;Luo Hui-Xia;He Jun-Feng(Department of Physics&CAS Key Laboratory of Strongly-coupled Quantum Matter Physics,University of Science and Technology of China,Hefei 230026,China;Paul Scherrer Institute,Villigen CH-5232;School of Materials Science and Engineering,Sun Yat-Sen University,Guangzhou 510275,China)

机构地区：[1]中国科学技术大学物理系,中科院强耦合量子材料物理重点实验室,合肥230026 [2]瑞士保罗谢尔研究所,菲利根CH-5232 [3]中山大学材料科学与工程学院,广州510275

出　　处：《物理学报》2022年第12期434-441,共8页Acta Physica Sinica

基　　金：中央高校基本科研业务费专项资金(批准号:WK2030000035,WK3510000008);中国科学技术大学启动经费资助的课题。

摘　　要：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.

关 键 词：过渡金属二硫族化物 角分辨光电子能谱 范霍夫奇点 电子-玻色子耦合 

分 类 号：O469[理学—凝聚态物理]