1. State Key Laboratory of Superhard MaterialsCollege of PhysicsJilin University Changchun 130012 P. R. China
2. Research Center for Functional MaterialsNational Institute for Materials Sciences Namiki 1-1 Tsukuba Ibaraki 305-0044 Japan
3. International Center for Materials Nanoarchitectonics (MANA)National Institute for Materials Science (NIMS) Namiki 1-1 Tsukuba Ibaraki 305-0044 Japan
4. Research Network and Facility Services DivisionNational Institute for Materials Science (NIMS) 1-2-1 Sengen Tsukuba Ibaraki 305-0047 Japan