1. School of Electronic and Information Engineering, School of Physics, Qingdao University 1 , Qingdao 266071, China
2. National Laboratory of Solid State Microstructures, Physics School, Nanjing University 2 , Nanjing 210093, People's Republic of China
3. Institute of Frontier and Interdisciplinary Science and Key Laboratory of Particle Physics and Particle Irradiation (MOE), School of Energy and Power Engineering, Shandong University 3 , Qingdao 266237, China