1. Department of Physics The Pennsylvania State University University Park PA 16802 USA
2. Physics Department and Research Center OPTIMAS Technische Universität Kaiserslautern Kaiserslautern 67663 Germany
3. Department of Mechanical Science and Engineering University of Illinois at Urbana‐Champaign Urbana IL 61801 USA
4. Center for Integrated Nanotechnologies Sandia National Laboratories Albuquerque, NM 87123 USA
5. Fraunhofer Institute for Industrial Mathematics ITWM Kaiserslautern 67663 Germany