1. Shenzhen Key Laboratory of Laser Engineering; College of Optoelectronic Engineering; Shenzhen University; Shenzhen 518060 China
2. National Laboratory of Solid State Microstructures; School of Physics; Collaborative Innovation Center of Advanced Microstructures; Nanjing University; Nanjing 210093 China
3. Department of Physics; Materials Genome Institute; International Centre for Quantum and Molecular Structures; and Shanghai Key Laboratory of High Temperature Superconductors; Shanghai University; Shanghai 200444 China
4. CNR-SPIN; Via Vetoio 10 I-67010 Coppito (L'Aquila) Italy