1. Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore
2. Tsinghua-Berkeley Shenzhen Institute and Shenzhen Geim Graphene Center, Tsinghua University, Shenzhen 518055, Guangdong, China
3. Agency for Science, Technology and Research (A*STAR), Institute of Materials Research and Engineering (IMRE), 2 Fusionopolis Way, Innovis #08-03, Singapore 138634, Singapore
4. Key Laboratory of Magnetic Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
5. School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Ave, Singapore 639798, Singapore
6. Energy and Environment (ISCE2), Agency for Science, Technology and Research (A*STAR), Institute of Sustainability for Chemicals, 1 Pesek Road, Jurong Island, Singapore 627833, Singapore
7. School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore
8. Tsinghua Shenzhen International Graduate School, Guangdong Provincial Key Laboratory of Thermal Management Engineering and Materials, Institute of Materials Research, Shenzhen 518055, Guangdong, China