1. Heilongjiang Province Key Laboratory of Superhard Materials, Department of Physics, Mudanjiang Normal University, Mudanjiang 157012, China
2. State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012, China
3. Shandong Key Laboratory of Optical Communication Science and Technology, School of Physics Science & Information Technology, Liaocheng University, Liaocheng 252059, China