1. Center for Correlated Electron Systems, Institute for Basic Science (IBS), Seoul 08826, Republic of Korea
2. Department of Materials Science and Engineering and Research Institute of Advanced Materials, Seoul National University, Seoul 08826, Republic of Korea
3. Department of Physics and Astronomy, Seoul National University, Seoul 08826, Republic of Korea
4. Department of Physics and Photon Science, Gwangju Institute of Science and Technology, Gwangju 61005, Republic of Korea
5. Department of Applied Quantum Physics and Nuclear Engineering, Kyushu University, Fukuoka 819-0395, Japan