1. Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 610054, P. R. China
2. School of Physics, University of Electronic Science and Technology of China, Chengdu 610054, P. R. China
3. Institut National de la Recherche Scientifique - Énergie Matériaux et Télécommunications, Varennes, QC J3X 1S2, Canada
4. Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan
5. Institute for Superconducting and Electronic Materials, Australian Institute for Innovative Materials, University of Wollongong, North Wollongong 2500, Australia