1. Department of Materials Science and Engineering Yonsei University Seoul 120–749 Korea
2. Center for Opto‐Electronic Materials and Devices Korea Institute of Science and Technology (KIST) Seongbuk‐gu Seoul 02792 South Korea
3. School of Integrated Technology College of Engineering Yonsei University 85 Songdogwahak‐ro Yeonsu‐gu Incheon 21983 Republic of Korea
4. Spin Convergence Research Center Korea Institute of Science and Technology (KIST) Seoul 02792 Republic of Korea