1. School of Physics and Electronics, Synergetic Innovation Center for Quantum Effects and Application, Key Laboratory of Low-dimensional Quantum Structures and Quantum Control of Ministry of Education, and Key Laboratory for Matter Microstructure and Function of Hunan Province, Hunan Normal University, Changsha 410081, P. R. China
2. School of Physics and Electronic Sciences, Hunan Provincial Key Laboratory of Flexible Electronic Materials Genome Engineering, Changsha University of Science and Technology, Changsha 410114, P. R. China
3. Institute of Interdisciplinary Studies, Hunan Normal University, Changsha 410081, P. R. China