1. Division of Materials Science & Chemical Engineering, Faculty of Engineering, Yokohama National University, 79-5 Tokiwadai, Hodogayaku, Yokohama 240-8501, Japan; Department of Physics, Graduate School of Science, and Center for Interdisciplinary Research, Tohoku University, Sendai, 980-8578, Japan; and Graduate School of Environment and Information Science, Yokohama National University, 79-5 Tokiwadai, Hodogayaku, Yokohama 240-8501, Japan