1. Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
2. Department of Physics, Lehigh University, Bethlehem, Pennsylvania 18015, United States
3. Van der Waals-Zeeman Institute, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
4. Department of Physics, West Chester University, West Chester, Pennsylvania 19383, United States