1. School of Industrial Engineering Purdue University West Lafayette IN 47907 USA
2. Birck Nanotechnology Centre Purdue University West Lafayette IN 47907 USA
3. Department of Physics Indian Institute of Technology Patna Bihta Campus Bihar 801106 India
4. Department of Mechanical and Aerospace Engineering University at Buffalo 240 Bell Hall Buffalo NY 14260‐4400 USA
5. School of Electrical and Computer Engineering Purdue University West Lafayette IN 47907 USA
6. Department of Physics University of Michigan Ann Arbor MI 48109 USA
7. School of Optical and Electronic Information Huazhong University of Science and Technology Wuhan 430074 China
8. Department of Materials Science and Engineering University of Michigan Ann Arbor MI 48109 USA
9. School of Materials Engineering Purdue University West Lafayette IN 47907 USA