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, ‡,}

Basic information of Na₃Bi. (a) Crystal structure of Na₃Bi. It consists of two Na₃Bi units in a unit cell and has an inversion center. (b) Brillouin zones of Na₃Bi. The hexagon and the rectangle are projected surface Brillouin zones of (001) and (100) surface, respectively. (c) XRD measurement on powder Na₃Bi sample which was sealed in an ultra thin quartz capillary shown in panel (e). Red and blue curves are XRD patterns of empty quartz capillary and the quartz capillary with Na₃Bi powder sealed inside, respectively. (d) shows their difference that represents the signal from the Na₃Bi powder sample. (f) XRD pattern on a Na₃Bi single crystal covered with Mylar thin film for protection from air. The right inset shows the picture of the measured sample. (g) Core levels of Na 2P_1/2, Na 2P_3/2 and Bi 5d_3/2, Bi 5d_5/2 in a photoemission spectrum taken with the incident photon energy of 56 eV.