Affiliation: | (1) Quantum-Functional Semiconductor Research Center, Dongguk University, Seoul, 100-715, Korea;(2) Department of Physics, Chungnum National University, Taejon, 305-764, Korea;(3) Department of Physics, Pusan National University, Pusan, 609-735, Korea;(4) Department of Physics, Faculty of Science, Science University of Tokyo, Tokyo, 162-8601, Japan |