1. Institute of Applied Physics and Computational Mathematics, Beijing 100088, China
2. Institute of Microelectronics, Tsinghua University, Beijing 100084, China
3. Beijing National Research Center for Information Science and Technology (BNRist), Tsinghua University, Beijing 100084, China
4. Department of Engineering Physics, Tsinghua University, Beijing 100084, China
5. Department of Physics, Tsinghua University, Beijing 100084, China