1. Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), Suwon16419, Republic of Korea
2. Institute for Quantum Biophysics, Department of Biophysics, Sungkyunkwan University, Suwon16419, Republic of Korea
3. Department of Energy Science and Department of Physics, Sungkyunkwan University, Suwon16419, Republic of Korea
4. Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee37830, United States