1. Department of Materials Science and Engineering, University of California, Berkeley, California 94720, United States
2. Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
3. Berkeley Sensor & Actuator Center, University of California, Berkeley, California 94720, United States
4. Electrical Engineering and Computer Sciences, University of California, Berkeley, California 94720, United States
5. The National Center for Electron Microscopy, Molecular Foundry, Berkeley, California 94720, United States