Measurement of the bulk and surface bands in Dirac line-node semimetal ZrSiS
Hong Guang-Hao1, 2, 4, Wang Cheng-Wei3, 4, Jiang Juan2, 5, 6, Chen Cheng7, Cui Sheng-Tao2, Yang Hai-Feng2, Liang Ai-Ji2, Liu Shuai2, Lv Yang-Yang8, Zhou Jian8, Chen Yan-Bin8, Yao Shu-Hua8, Lu Ming-Hui8, Chen Yan-Feng8, Wang Mei-Xiao2, Yang Le-Xian9, Liu Zhong-Kai2, †, Chen Yu-Lin2, 7, 9, ‡
       

(color online) Characterization of ZrSiS single crystals and Dirac line node. (a) PbFCl-type structure of ZrSiS crystal, lattice constants (a = b = 3.544 Å, c = 8.055 Å) and cleavage plane are labelled. (b) The schematics of Dirac node and Dirac line node in the momentum space. (c) Calculation results of the bulk band structure of ZrSiS along high-symmetry directions. The green line indicates the position of the Dirac line node. (d) Illustration of the Dirac line-node location (labelled by the solid green line) in Brillouin zone boundary along the X–R direction. In addition, the projected surface BZ of (001) plane is also labelled. (e) Core level photoemission spectrum of ZrSiS showing the characteristic Zr4s, Zr4p, and Si2p peaks. Left inset: cleaved surface of ZrSiS single crystal used in this study. Right inset: Laue pattern showing the high quality of the ZrSiS crystal. (f) Broad range photoemission spectral intensity map of the Fermi-surface covering more than one BZ, showing the correct symmetry and the characteristic of the FS.