Zhang Kai-Wen, Yang Chao-Long, Lei Bin, Lu Pengchao, Li Xiang-Bing, Jia Zhen-Yu, Song Ye-Heng, Sun Jian, Chen Xianhui, Li Jian-Xin, Li Shao-Chun
National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing 210093, China.
Hefei National Laboratory for Physical Science at Microscale and Department of Physics, University of Science and Technology of China, Hefei 230026, China.
Sci Bull (Beijing). 2018 Apr 15;63(7):426-432. doi: 10.1016/j.scib.2018.02.018. Epub 2018 Mar 21.
By using scanning tunneling microscopy (STM)/spectroscopy (STS), we systematically characterize the electronic structure of lightly doped 1T-TiSe, and demonstrate the existence of the electronic inhomogeneity and the pseudogap state. It is found that the intercalation induced lattice distortion impacts the local band structure and reduce the size of the charge density wave (CDW) gap with the persisted 2 × 2 spatial modulation. On the other hand, the delocalized doping electrons promote the formation of pseudogap. Domination by either of the two effects results in the separation of two characteristic regions in real space, exhibiting rather different electronic structures. Further doping electrons to the surface confirms that the pseudogap may be the precursor for the superconducting gap. This study suggests that the competition of local lattice distortion and the delocalized doping effect contribute to the complicated relationship between charge density wave and superconductivity for intercalated 1T-TiSe.
通过使用扫描隧道显微镜（STM）/能谱（STS），我们系统地表征了轻掺杂1T-TiSe₂的电子结构，并证明了电子不均匀性和赝能隙态的存在。研究发现，插层诱导的晶格畸变影响局部能带结构，并减小电荷密度波（CDW）能隙的大小，同时保持2×2空间调制。另一方面，离域掺杂电子促进了赝能隙的形成。这两种效应中的任何一种占主导地位都会导致实空间中两个特征区域的分离，呈现出相当不同的电子结构。向表面进一步掺杂电子证实，赝能隙可能是超导能隙的前驱体。这项研究表明，局部晶格畸变和离域掺杂效应的竞争导致了插层1T-TiSe₂中电荷密度波与超导性之间的复杂关系。
