[1] Nanyang Technol Univ, Sch Mat Sci & Engn, Ctr Programmable Mat, 50 Nanyang Ave, Singapore 639798, Singapore
[2] Chinese Acad Sci, Inst Phys, Beijing Natl Lab Condensed Matter Phys, Beijing 100190, Peoples R China
[3] Univ Chinese Acad Sci, Sch Phys Sci, Beijing 100049, Peoples R China
[4] ASTAR, Inst Mat Res & Engn, 2 Fusionopolis Way,Innovis 08-03, Singapore 138634, Singapore
[5] Collaborat Innovat Ctr Quantum Matter, Beijing 100190, Peoples R China