1. Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany;
2. Scottish Universities Physics Alliance, School of Physics and Astronomy, University of St Andrews, St Andrews KY16 9SS, United Kingdom;
3. National Institute for Materials Science, Tsukuba 305-0003, Japan;
4. ISIS Facility, Science and Technology Facilities Council Rutherford Appleton Laboratory, Didcot OX11 0QX, United Kingdom;
5. Department of Physics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan;
6. Institut für Theorie der Kondensierten Materie, Karlsruher Institut für Technologie, 76131 Karlsruhe, Germany;
7. Institut für Quantenmaterialien und Technologien, Karlsruher Institut für Technologie, 76131 Karlsruhe, Germany