1. Materials
Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
2. Center
for Electron Microscopy Research, Korea Basic Science Institute, Daejeon 34133, South Korea
3. Center
for Integrated Nanostructure Physics, Institute for Basic Science (IBS), Suwon 16419, Republic of Korea
4. Department
of Energy Science, Sungkyunkwan University (SKKU), Suwon 16419, Republic of Korea
5. Department
of Mechanical Engineering and Materials Science, Washington University in St. Louis, St. Louis, Missouri 63130, United States
6. Center for
Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
7. Department
of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee 37235, United States
8. Department
of Materials Science and Engineering, National University of Singapore, 117575, Singapore