1. Layered Materials and Device Physics Laboratory, Department of Chemistry, Physics and Atmospheric Science, Jackson State University, Jackson, MS 39217, USA
2. National High Magnetic Field Laboratory, 1800 E. Paul Dirac Dr., Tallahassee, FL 32310, USA
3. Department of Physics, Florida State University, 77 Chieftan Way, Tallahassee, FL 32306, USA
4. Center for Nanoscale Materials, Argonne National Laboratory, 9700 S-Cass Avenue, Lemont, IL-60439, USA
5. Department of Electrical Engineering, Indian Institute of Technology Madras, Chennai, Tamil Nadu-600036, India
6. Department of Physics, Baylor University, One Bear Place 97316, Waco, TX 76798-7316, USA
7. Department of Physics, University of South Florida, Tampa, FL 33620, USA