1. Department of Physics and Astronomy, Purdue University 1 , West Lafayette, Indiana 47907, USA
2. Institute of Physics and Astronomy and Villum Center for Hybrid Quantum Materials and Devices, Aarhus University 2 , 8000 Aarhus-C, Denmark
3. Birck Nanotechnology Center, Purdue University 3 , West Lafayette, Indiana 47907, USA
4. Purdue Quantum Science and Engineering Institute and School of Electrical and Computer Engineering, Purdue University 4 , West Lafayette, Indiana 47907, USA