1. Material, Physical and Chemical Sciences Center, Sandia National Laboratories, Albuquerque, NM 87123, USA.
2. Institute for Applied Materials, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany.
3. Department of Microsystems Engineering, University of Freiburg, 79110 Freiburg, Germany.
4. Department of Mechanical Engineering, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland.
5. Freiburg Materials Research Center, University of Freiburg, 79104 Freiburg, Germany.
6. Cluster of Excellence livMatS, University of Freiburg, 79110 Freiburg, Germany.