1. Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China
2. School of Mathematics and Physics, China University of Geosciences (Wuhan), Wuhan 430074, China
3. Department of Physics, Florida A&M University, Tallahassee, Florida 32307, United States
4. Department of Physics and High Pressure Science and Engineering Center, University of Nevada, Las Vegas, Nevada 89154, United States