Feng Tang1,2, Hoi Chun Po3,4, Ashvin Vishwanath3 & Xiangang Wan1,2*
1 National Laboratory of Solid State Microstructures and School of Physics, Nanjing University, Nanjing, China.
2 Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, China.
3 Department of Physics, Harvard University, Cambridge, MA, USA.
4 Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA.