1. Department of Physics, Graduate School of Science, University of Tokyo, Bunkyo, Tokyo 113-0033, Japan
2. Department of Physics and Astronomy, University of British Columbia, Vancouver BC V6T 1Z2, Canada
3. Institute for Functional Matter and Quantum Technologies, University of Stuttgart, 70569 Stuttgart, Germany
4. Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, Germany