1. State Key Laboratory of Material Processing and Die and Mould TechnologySchool of Materials Science and EngineeringHuazhong University of Science and Technology (HUST) Wuhan 430074 P. R. China
2. Beijing Center for Crystal R&DKey Lab of Functional Crystals and Laser Technology of Chinese Academy of SciencesTechnical Institute of Physics and ChemistryChinese Academy of Sciences Beijing 100190 P. R. China
3. NRC (Nanostructure Research Centre)State Key Laboratory of Advanced Technology for Materials Synthesis and ProcessingInternational School of Materials Science and EngineeringWuhan University of Technology (WUT) Wuhan 430070 P. R. China
4. EMAT (Electron Microscopy for Materials Science)University of Antwerp Groenenborgerlaan 171 2020 Antwerp Belgium
5. Division of Physics and Applied PhysicsSchool of Physical and Mathematical SciencesNanyang Technological University Singapore 637371 Singapore