1. Institute of Applied Physics and Wüzburg-Dresden Cluster of Excellence ct.qmat, Technische Universität Dresden, 01062 Dresden, Germany
2. Department of Physics, University of Regensburg, 93053 Regensburg, Germany
3. Ioffe Institute, 194021 Saint Petersburg, Russian Federation
4. International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Ibaraki 305-004, Japan
5. Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Ibaraki 305-004, Japan