1. Department of Physics and Shenzhen Key Laboratory of Advanced Quantum Functional Materials and Devices Southern University of Science and Technology Shenzhen 518055 China
2. School of Physics and Electronics Hunan Key Laboratory for Super‐Micro Structure and Ultrafast Process Central South University 932 South Lushan Road Changsha 410083 China
3. Department of Physics and Astronomy and Department of Electrical and Computer Engineering Vanderbilt University Nashville TN 37235 USA