1. Elmore Family School of Electrical and Computer Engineering, Birck Nanotechnology Center and Purdue Quantum Science and Engineering Institute Purdue University 610 Purdue Mall West Lafayette IN 47907 USA
2. Quantum Science Center, Department of Energy, A National Quantum Information Science Research Center of the U.S Oak Ridge National Laboratory 1 Bethel Valley Road Oak Ridge TN 37830 USA
3. Materials Science and Technology Division Oak Ridge National Laboratory 1 Bethel Valley Road Oak Ridge TN 37830 USA