1. Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ 08544, USA.
2. Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany.
3. SZU-NUS Collaborative Center and International Collaborative Laboratory of 2D Materials for Optoelectronic Science and Technology, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China.
4. Department of Physics and Astronomy, University of Missouri, Columbia, MO 65211, USA.
5. Department of Physics, National Cheng Kung University, Tainan 701, Taiwan.
6. Department of Physics, National Sun Yat-Sen University, Kaohsiung 804, Taiwan.
7. Department of Physics, Northeastern University, Boston, MA 02115, USA.
8. Institute of Physics, Academia Sinica, Taipei 11529, Taiwan.
9. Princeton Institute for Science and Technology of Materials, Princeton University, Princeton, NJ, 08544, USA.
10. Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.