Electronic structure, Dirac points and Fermi arc surface states in three-dimensional Dirac semimetal Na<sub>3</sub>Bi from angle-resolved photoemission spectroscopy

Electronic structure, Dirac points and Fermi arc surface states in three-dimensional Dirac semimetal Na₃Bi from angle-resolved photoemission spectroscopy

Liang Aiji¹, Chen Chaoyu¹, Wang Zhijun¹, Shi Youguo¹, Feng Ya¹, Yi Hemian¹, Xie Zhuojin¹, He Shaolong^{1, †,}, He Junfeng¹, Peng Yingying¹, Liu Yan¹, Liu Defa¹, Hu Cheng¹, Zhao Lin¹, Liu Guodong¹, Dong Xiaoli¹, Zhang Jun¹, Nakatake M², Iwasawa H², Shimada K², Arita M², Namatame H², Taniguchi M², Xu Zuyan³, Chen Chuangtian³, Weng Hongming^{1, 4}, Dai Xi^{1, 4}, Fang Zhong^{1, 4}, Zhou Xing-Jiang^{1, 4, ‡,}

Detection of the two three-dimensional Dirac cones along the k_z direction. (a) The sketch of the bulk Brillouin zone of Na₃Bi. Two three-dimensional bulk Dirac nodes are labeled as + k_zc and −k_zc along the A–Γ–A direction. (b) The extracted energy position of the α band top as a function of k_z calculated from different photon energies shown in panel (c). The gray dashed line is the guide to eyes. (c) Band structures measured on the (001) surface of Na₃Bi along direction at different photon energies. The images are obtained by taking EDC second-derivative of the original data. The red dashed lines are fitted curves considering the Dirac cone shape. (d) Calculated band structure along direction at different k_zs. The bands at a critical k_zc in (d3) show a Dirac point. The slopes of α and β bands are around 1.5 eV·Å and 2.7 eV·Å, respectively.