Shengyan Yang,†,§,a Zhe Liu,†,||,a Sha Hu,†,§ Ai-Zi Jin,†,⊥ Haifang Yang,†,⊥ Shuang Zhang,*,‡ Junjie Li,*,†,⊥ and Changzhi Gu*,†,§
† Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
‡ School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT, U.K.
§ School of Physical Sciences, CAS Key Laboratory of Vacuum Physics, University of Chinese Academy of Sciences, Beijing 100049, China
|| Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, DK-2100 Copenhagen, Denmark
⊥ Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
a S.Y. and Z.L. contributed equally to this work.