1. Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
2. Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States
3. Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
4. Department of Physics, University of Illinois, Chicago, Illinois 60607-7059, United States
5. Department of Physics and Institute of Quantum Convergence Technology, Kangwon National University, Chuncheon 24341, Korea
6. Department of Physics, University of Tennessee, Knoxville, Tennessee 37996, United States