1. a Department of Physics and Astronomy , University of Texas at San Antonio , San Antonio, Texas, 78249, USA
2. b The TcSUH , the University of Houston , Houston, TX, 77204, USA
3. c Department of Materials Science and Engineering , University of Texas at Arlington , Arlington, Texas, 76019, USA
4. d Department of Electrical & Computer Engineering , University of Texas at San Antonio , San Antonio, Texas, 78249, USA
5. e Department of Mechanical Engineering , University of South Carolina , Columbia, SC, 29208, USA
6. f US Army Research Laboratory , Aberdeen Proving Ground, MD, 21005, USA