1. Materials Science and Engineering Program and Texas Materials Institute, The University of Texas at Austin, Austin, TX 78712, USA.
2. Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, TX 78705, USA.
3. Walker Department of Mechanical Engineering, The University of Texas at Austin, Austin, TX 78712, USA.
4. School of Physics and Information Technology, Shaanxi Normal University, Xi’an, Shaanxi 710062, China.