1. School of Physics, University of New South Wales, Sydney, NSW 2052, Australia
2. Australian Research Council
Centre of Excellence for Quantum Computation and Communication Technology, University of New South Wales, Sydney, NSW 2052, Australia
3. Dipartimento di Fisica “E.
Amaldi”, Università di Roma Tre, Via della Vasca Navale 84, 00146 Roma, Italy
4. Department of Materials Science
and Engineering, University of North Texas, Denton, Texas 76209, United States
5. Department of Materials Science
and Engineering, Colorado School of Mines, Golden, Colorado 80401, United States