title: Novel lithium-nitrogen compounds at ambient and high pressures.
abstract: Using ab initio evolutionary simulations, we predict the existence of five novel stable Li-N compounds at pressures from 0 to 100 GPa (Li13N, Li5N, Li3N2, LiN2, and LiN5). Structures of these compounds contain isolated N atoms, N2 dimers, polyacetylene-like N chains and N5 rings, respectively. The structure of Li13N consists of Li atoms and Li12N icosahedra (with N atom in the center of the Li12 icosahedron) - such icosahedra are not described by Wade-Jemmis electron counting rules and are unique. Electronic structure of Li-N compounds is found to dramatically depend on composition and pressure, making this system ideal for studying metal-insulator transitions. For example, the sequence of lowest-enthalpy structures of LiN3 shows peculiar electronic structure changes with increasing pressure: metal-insulator-metal-insulator. This work also resolves the previous controversies of theory and experiment on Li2N2.
authors.affiliation: Department of Physics, Harbin Institute of Technology, Harbin 150001, China.|Department of Geosciences, Center for Materials by Design, and Institute for Advanced Computational Science, Stony Brook University, Stony Brook, New York 11794, USA.
authors.forename: Yanqing
authors.initials: Y
authors.lastname: Shen
authors.affiliation: Skolkovo Institute of Science and Technology, Skolkovo Innovation Center, 3 Nobel St., Moscow 143026, Russia.|Moscow Institute of Physics and Technology, 9 Institutskiy Lane, Dolgoprudny City, Moscow Region 141700, Russia.|Department of Geosciences, Center for Materials by Design, and Institute for Advanced Computational Science, Stony Brook University, Stony Brook, New York 11794, USA.|School of Materials Science, Northwestern Polytechnical University, Xi'an 710072, China.
authors.forename: Artem R
authors.initials: AR
authors.lastname: Oganov
authors.affiliation: Department of Geosciences, Center for Materials by Design, and Institute for Advanced Computational Science, Stony Brook University, Stony Brook, New York 11794, USA.
authors.forename: Guangri
authors.initials: G
authors.lastname: Qian
authors.affiliation: Department of Geosciences, Center for Materials by Design, and Institute for Advanced Computational Science, Stony Brook University, Stony Brook, New York 11794, USA.
authors.forename: Jin
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Department of Geosciences, Center for Materials by Design, and Institute for Advanced Computational Science, Stony Brook University, Stony Brook, New York 11794, USA.
authors.forename: Huafeng
authors.initials: H
authors.lastname: Dong
authors.affiliation: Department of Geosciences, Center for Materials by Design, and Institute for Advanced Computational Science, Stony Brook University, Stony Brook, New York 11794, USA.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Zhu
authors.affiliation: Department of Physics, Harbin Institute of Technology, Harbin 150001, China.
authors.forename: Zhongxiang
authors.initials: Z
authors.lastname: Zhou