1. Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui 230026, People’s Republic of China
2. II. Physikalisches Institut, Universität zu Köln, Zülpicher Strasse 77, D-50937 Köln, Germany
3. School of Physical Sciences, University of Science and Technology of China, Hefei, Anhui 230026, People’s Republic of China
4. Key Laboratory of Strongly-Coupled Quantum Matter Physics, Chinese Academy of Sciences, Hefei, Anhui 230026, People’s Republic of China
5. Collaborative Innovation Center of Advanced Microstructures, Nanjing, Jiangsu 210093, People’s Republic of China