1. State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou 310027, People’s Republic of China, Solid-State Physics and Magnetism Section, Department of Physics and Astronomy, Katholieke Universiteit Leuven, Celestijnenlaan 200 D, BE-3001 Leuven, Belgium, and Microanalysis of Materials, Faculty of Engineering, Christian-Albrechts-University (CAU) Kiel, Kaiserstrasse 2, 24143 Kiel, Germany