1. Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee 37235, United States
2. Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
3. Department of Physics, Indiana University, Bloomington, Indiana 47405, United States
4. Elmore Family School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana 47907, United States
5. Department of Physics and Astronomy, Purdue University, West Lafayette, Indiana 47907, United States
6. Quantum Science Center, Oak Ridge, Tennessee 37831, United States
7. Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States