1. School of Physics National Laboratory of Solid State Microstructures and Collaborative Innovation Center of Advanced Microstructures Nanjing University Nanjing 210093 P. R. China
2. Collaborative Innovation Center for Information Technology in Biological and Medical Physics, and College of Science Zhejiang University of Technology Hangzhou 310023 P. R. China
3. Department of Electrical Engineering‐Electrophysics University of Southern California Los Angeles CA 90089 USA
4. Department of Materials Science and Engineering University of California Los Angeles Los Angeles CA 90095 USA
5. Jonsson Comprehensive Cancer Center University of California Los Angeles Los Angeles CA 90024 USA