1. Department of Physics; The University of Texas at Arlington; Arlington TX USA
2. Department of Electrical Engineering; The University of Texas at Arlington; Arlington TX USA
3. Department of Materials Science and Engineering; The University of Texas at Arlington; Arlington TX USA
4. Center for Functional Nanomaterials; Brookhaven National Laboratory; Upton NY USA
5. National Laboratory of Solid State Microstructures and Department of Materials Science and Engineering; Nanjing University; Nanjing 210093 China
6. Physical Sciences Division; Pacific Northwest National Laboratory; Richland WA USA
7. Environmental Molecular Sciences Laboratory; Pacific Northwest National Laboratory; Richland WA USA