title: 2D materials: Metallic when narrow.
authors.affiliation: Key Laboratory of Intelligent Nano Materials and Devices of Ministry of Education, State Key Laboratory of Mechanics and Control of Mechanical Structures, Institute of Nano Science of Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China.
authors.forename: Wanlin
authors.initials: W
authors.lastname: Guo
authors.affiliation: Key Laboratory of Intelligent Nano Materials and Devices of Ministry of Education, State Key Laboratory of Mechanics and Control of Mechanical Structures, Institute of Nano Science of Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China.
authors.forename: Xiaofei
authors.initials: X
authors.lastname: Liu