1. Korea Institute of Fusion Energy (KFE), Daejeon 34133, Republic of Korea
2. Department of Physics, Kunsan National University, Gunsan 54150, Republic of Korea
3. The Institute of Basic Science, Kunsan National University, Gunsan 54150, Republic of Korea
4. Renewable Energy Materials Laboratory (REML), Advanced Institute of Convergence Technology (AICT), Seoul National University, Suwon 16229, Republic of Korea