1. Department of Molecular EngineeringGraduate School of EngineeringKyoto University Nishikyo‐ku Kyoto 615‐8510 Japan
2. Division of ElectricalElectronic and Information EngineeringOsaka University 2‐1 Yamadaoka Suita Osaka 565‐0871 Japan
3. Institute of Multidisciplinary Research for Advanced MaterialsTohoku University Sendai 980‐8577 Japan