1. Beijing National Laboratory for Condensed Matter Physics and Institute of PhysicsChinese Academy of Sciences Beijing 100190 China
2. School of Physical SciencesUniversity of Chinese Academy of Sciences Beijing 100049 China
3. Department of PhysicsUniversity of Virginia Charlottesville VA 22901 USA
4. Songshan Lake Materials Laboratory Dongguan 523808 China
5. Beijing Academy of Quantum Information Sciences Beijing 100193 China