1. School of Materials Engineering and Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, United States
2. School of Mechanical Engineering, Purdue University, West Lafayette, Indiana 47907, United States
3. Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
4. Department of Engineering Science, University of Oxford, Parks Road, OX1 3PJ Oxford, United Kingdom
5. Department of Mechanical Engineering, Wayne State University, Detroit, Michigan 48202, United States