[1] Beijing Normal Univ, Ctr Adv Quantum Studies, Beijing 100875, Peoples R China
[2] Beijing Normal Univ, Dept Phys, Beijing 100875, Peoples R China
[3] Univ Twente, Fac Sci & Technol, POB 217, NL-7500 AE Enschede, Netherlands
[4] Univ Twente, MESA Inst Nanotechnol, POB 217, NL-7500 AE Enschede, Netherlands