1. Intercollege Graduate Degree Program in Materials Science and Engineering, Pennsylvania State University, University Park, Pennsylvania 16802, USA
2. Department of Physics, University of Evansville, Evansville, Indiana 47722, USA
3. Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa 52242, USA
4. Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, Pennsylvania 16802, USA