1. Center
for Computational Science, Korea Institute of Science and Technology, Seoul 02792, Korea
2. Department
of Physics, Ulsan National Institute of Science and Technology, Ulsan 44919, Korea
3. School
of Materials Science and Engineering, Yeungnam University, Gyeongsangbuk-do 38541, Korea
4. Department
of Nanomaterials Science and Engineering, Korea University of Science and Technology, Daejeon 34113, Korea