1. Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Shenyang National Laboratory for Materials Science, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
2. Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China
3. National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
4. Department of Optical Engineering, Kongju National University, Cheonan 31080, Korea
5. Department of Physics, University of California at Berkeley, Berkeley, California 94720, United States
6. Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
7. Kavli Energy NanoSciences Institute, University of California, Berkeley and the Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States