1. RIKEN Center for Emergent Matter Science, Wako-shi, Saitama 351-0198, Japan
2. Physics & Informatics Laboratories (PHI Lab), NTT Research, Inc., Sunnyvale, California 94085, United States
3. Institute of Physics, University of Oldenburg, D-26129 Oldenburg, Germany
4. Technische Physik, Physikalisches Institut and Wilhelm Conrad Roentgen-Research Center for Complex Material System, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany