1. Department of Engineering, The Nanoscience Centre, University of Cambridge, Cambridge CB3 0FF, United Kingdom
2. Silicon Microgravity Ltd., Cambridge, Innovation Park, Cambridge CB25 9PB, United Kingdom
3. MOE Key Laboratory of Fundamental Physical Quantities Measurement and Hubei Key Laboratory of Gravitation and Quantum Physics, PGMF and School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China