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, ‡,}

Direct observation of a pair of three-dimensional Dirac cones on the (100) surface of Na₃Bi. (a) Fermi surface near the zone center measured on the (100) surface with a photon energy of 56 eV. The two spot-like features along the direction, symmetrically located with respect to the zone center, are associated with the three-dimensional bulk Dirac nodes in Na₃Bi. (b) Energy position of the α band top (red cirlces) in panel (c) as a function of k_z. The gray dashed line is the guide to the eyes. (c) Band structures taken at different k_z along the direction as sketched in panel (b). The band images are obtained by the second derivative of the original data with respect to the energy. The red dashed lines are fitted curves considering the Dirac cone shape.