1. Institute
of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China
2. Department
of Physics, Nanyang Normal University, Nanyang 473061, China
3. Department
of Physics and Optoelectronic Engineering, Yangtze University, Jingzhou 434023, China
4. Department
of Physics and High Pressure Science and Engineering Center, University of Nevada, Las Vegas, Nevada 89154, United States
5. Departamento
de Física Aplicada, Centro de Investigación y de Estudios Avanzados, Unidad Mérida, Km 6 Antigua Carretera a Progreso, Apdo. Postal 73, Cordemex, 97310 Mérida, Yucatán, Mexico