[1] Natl Ctr Nanosci & Technol, Beijing 100080, Peoples R China
[2] Nagoya Univ, Ctr Integrated Res Sci & Engn, Chikusa Ku, Nagoya, Aichi 4648603, Japan
[3] Aichi Sci & Technol Fdn, Nagoya, Aichi 460002, Japan
[4] Chinese Acad Sci, Inst Phys, Ctr Condensed Matter Phys, Beijing 100080, Peoples R China