1. Center for Spintronics Research Network (CSRN); The University of Tokyo; 7-3-1 Hongo, Bunkyo Tokyo 113-8656 Japan
2. Department of Electrical Engineering and Information Systems; The University of Tokyo; 7-3-1 Hongo, Bunkyo Tokyo 113-8656 Japan
3. Institute for Nano Quantum Information Electronics; The University of Tokyo; 7-3-1 Hongo, Bunkyo Tokyo 113-8656 Japan