Q. Li¹, G. Chen², T. P. Ma¹, J. Zhu¹, A. T. N'Diaye³, L. Sun¹, T. Gu¹, Y. Huo¹, J. H. Liang¹, R. W. Li⁴, C. Won⁵, H. F. Ding⁶, Z. Q. Qiu^7,*, and Y. Z. Wu^1,†

• ¹Department of Physics, State Key Laboratory of Surface Physics and Collaborative Innovation Center of Advanced Microstructures, Fudan University, Shanghai 200433, People's Republic of China
• ²NCEM, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
• ³Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
• ⁴Chinese Academy of Sciences, Ningbo Institute of Materials Technology and Engineering, Key Laboratory of Magnetic Materials and Devices, Ningbo 315201, Zhejiang, People's Republic of China
• ⁵Department of Physics, Kyung Hee University, Seoul 130-701, Republic of Korea
• ⁶National Laboratory of Solid State Microstructures, Department of Physics and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, 22 Hankou Road, Nanjing 210093, People's Republic of China
• ⁷Department of Physics, University of California at Berkeley, Berkeley, California 94720, USA

• ^*Electronic address: qiu@berkeley.edu
• ^†Electronic address: wuyizheng@fudan.edu.cn