title: Thermal exfoliation of stoichiometric single-layer silica from the stishovite phase: insight from first-principles calculations.
abstract: Mechanical cleavage, chemical intercalation and chemical vapor deposition are the main methods that are currently used to synthesize nanosheets or monolayers. Here, we propose a new strategy, thermal exfoliation for the fabrication of silica monolayers. Using a variety of state-of-the-art theoretical calculations we show that a stoichiometric single-layer silica with a tetragonal lattice, T-silica, can be thermally exfoliated from the stishovite phase in a clean environment at room temperature. The resulting single-layer silica is dynamically, thermally, and mechanically stable with exceptional properties, including a large band gap of 7.2 eV, an unusual negative Poisson's ratio, a giant Stark effect, and a high breakdown voltage. Moreover, other analogous structures like single-layer GeO2 can also be obtained by thermal exfoliation of its bulk phase. Our findings are expected to motivate experimental efforts on developing new techniques for the synthesis of monolayer materials.
authors.affiliation: Center for Applied Physics and Technology, College of Engineering, Peking University, Key Laboratory of High Energy Density Physics Simulation, and IFSA Collaborative Innovation Center, Ministry of Education, Beijing 100871, China. qianwang2@pku.edu.cn and Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871, China.
authors.forename: Yaguang
authors.initials: Y
authors.lastname: Guo
authors.affiliation: Center for Applied Physics and Technology, College of Engineering, Peking University, Key Laboratory of High Energy Density Physics Simulation, and IFSA Collaborative Innovation Center, Ministry of Education, Beijing 100871, China. qianwang2@pku.edu.cn and Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871, China.
authors.forename: Shunhong
authors.initials: S
authors.lastname: Zhang
authors.affiliation: Center for Applied Physics and Technology, College of Engineering, Peking University, Key Laboratory of High Energy Density Physics Simulation, and IFSA Collaborative Innovation Center, Ministry of Education, Beijing 100871, China. qianwang2@pku.edu.cn and Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871, China.
authors.forename: Tianshan
authors.initials: T
authors.lastname: Zhao
authors.affiliation: Center for Applied Physics and Technology, College of Engineering, Peking University, Key Laboratory of High Energy Density Physics Simulation, and IFSA Collaborative Innovation Center, Ministry of Education, Beijing 100871, China. qianwang2@pku.edu.cn and Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871, China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Wang