1. Physical Science and Engineering Division (PSE) King Abdullah University of Science and Technology (KAUST) Thuwal 23955–6900 Saudi Arabia
2. Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education School of Physical Science and Technology Lanzhou University Lanzhou 730000 China
3. School of Materials and Energy and Electron Microscopy Centre of Lanzhou University Lanzhou University Lanzhou 730000 China
4. State Key Laboratory of Electronic Thin Film and Integrated Devices University of Electronic Science and Technology of China Chengdu 610054 China
5. Guangdong Provincial Key Laboratory of Optical Information Materials and Technology & Institute for Advanced Materials South China Academy of Advanced Optoelectronics South China Normal University Guangzhou 510006 China
6. National Center for International Research on Green Optoelectronics South China Normal University Guangzhou 510006 China
7. Physics Department Georgetown University Washington, DC 20057 USA