1. Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, USA
2. School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA
3. Kavli Institute at Cornell for Nanoscale Science, Ithaca, New York 14853, USA
4. Samsung Advanced Institute of Technology (SAIT), Samsung Electronics, 130 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do 16678, South Korea
5. Heeg Vacuum Engineering, Kerpen, Germany
6. Quantum Designed Materials Ltd., Rehovot, Israel
7. National Laboratory of Solid State Microstructures, College of Engineering and Applied Sciences, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, China
8. Leibniz-Institut für Kristallzüchtung, Max-Born-Str. 2, Berlin 12489, Germany