1. Materials Genome InstituteShanghai University Shanghai 200444 China
2. Energy Materials and Surface Sciences Unit (EMSSU)Okinawa Institute of Science and Technology Graduate University (OIST) 1919‐1 Tancha Onna‐son Okinawa 904‐0495 Japan
3. Institute of Applied PhysicsUniversity of Tsukuba Tsukuba Ibaraki 305‐8573 Japan
4. Department of PhysicsThe Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong China