1. Center for Advancing Materials Performance from the Nanoscale (CAMP-NANO) and Hysitron Applied Research Center in China (HARCC), State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an 710049, P. R. China
2. Department of Physics, The Hong Kong University of Science and Technology, Hong Kong, P.R. China
3. Institute of Materials Physics, University of Göttingen, Göttingen 37077, Germany
4. Department of Materials Science and Engineering, University of California, Berkeley, California 94720, United States
5. National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, United States