For Submission to Nature Materials
Supporting Information for
Revealing spatial orbital nature of Bi2Se3 
Jingwei Dong1, 2#, Jiuxiang Zhang3#, Zailan Zhang4#, Zhanfeng Liu5, Yi Liu5, Zhe Sun5, Xiaoen Wang1, 2, Zhesheng Chen6*, Zhongwei Chen1, 2*

1Power Battery & Systems Research Center, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, P. R. China; 
2State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, P. R. China
3Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, P. R. China
4School of Physics, Nanjing University of Science and Technology, Nanjing, 210094, P. R. China
5National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, P. R. China
6School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing, 210094, P. R. China

#These authors contribute equally to this work.
*To whom correspondence should be addressed.
zwchen@dicp.ac.cn;  zhesheng.chen@njust.edu.cn

Figure S1. Constant-energy contours for the BVB (A), SSB (B) and BCB (C) with a R60 operation acquired at the binding energy of 0.6 eV, 0.2 eV and 0.02 eV with a set of photon energies under p-polarization. The green, yellow and red curves represent the momentum distribution curves (MDCs) extracted at kx = 0 (1/Å) and the white arrow lines mark the extreme cut-off points of MDCs.