1. School of Physics and Key Laboratory of MEMS of the Ministry of EducationSoutheast University Nanjing 211189 P. R. China
2. Center for High Pressure Science and Technology Advanced Research Shanghai 201203 China
3. Information Physics Research CenterNanjing University of Posts and Telecommunications Nanjing 210023 China
4. Key Laboratory of Polar Materials and Devices, Ministry of Education Department of Electronic EngineeringEast China Normal University Shanghai 200241 China
5. Key Laboratory of Advanced Micro/Nano Functional Materials of Henan Province, School of Physics and Electronic EngineeringXinyang Normal University Xinyang 464000 China