1. Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
2. Thin Film Physics Division, Department of Physics, Chemistry, and Biology (IFM), Linköping University, Linköping SE-581 83, Sweden
3. Guangdong Provincial Key Laboratory of Functional Oxide Materials and Devices, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China