1. State Key Laboratory of Low Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing, 100084, China
2. Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, United States
3. Department of Physics and Astronomy, Stony Brook University, Stony Brook, New York 11794, United States
4. Tsinghua-Foxconn Nanotechnology Research Center, Tsinghua University, Beijing, 100084, China
5. Collaborative Innovation Center of Quantum Matter, Beijing 100084, China