[1] Chinese Acad Sci, Beijing Natl Lab Condensed Matter Phys, Beijing 100190, Peoples R China
[2] Chinese Acad Sci, Inst Phys, Beijing 100190, Peoples R China
[3] Collaborat Innovat Ctr Quantum Matter, Beijing, Peoples R China
[4] Brookhaven Natl Lab, Condensed Matter Phys & Mat Sci Dept, Upton, NY 11973 USA
[5] Argonne Natl Lab, Adv Photon Source, Argonne, IL 60439 USA
[6] Univ Kentucky, Dept Phys & Astron, Ctr Adv Mat, Lexington, KY 40506 USA