title: Layered polymeric nitrogen in RbN3 at high pressures.
abstract: The structural evolutionary behaviors of nitrogen in RbN3 have been studied up to 300 GPa using a particle swarm optimization structure searching method combined with density functional calculations. Three stable new phases with P-1, P6/mmm and C2/m structure at pressure of 30, 50 and 200 GPa are identified for the first time. The analysis of the crystal structures of three new predicated phases reveals that the transition of N3- ions goes from linear molecules to polymeric chains, benzene-like rings and then to polymeric layers induced by pressure. The electronic structures of three predicted phases reveal that the structural changes are accompanied and driven by the change of orbital hybridization of N atoms from sp to sp(2) and finally to partial sp(3). Most interestingly, the Rb atoms show obvious transition metal-like properties through the occupation of 4d orbitals in high-pressure phases. Moreover, the Rb atoms are characterized by strong hybridization between 4d orbitals of Rb and 2p orbitals of N in C2/m structure. Our studies complete the structural evolution of RbN3 under pressure and reveal for the first time that the Rb atoms in rubidium nitride possess transition element-like properties under pressure.
authors.affiliation: Institute of Condensed Matter Physics, Linyi University, Linyi 276005, P. R. China.|Beijing Computational Science Research Center, Beijing, 100084, P. R. China.
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Wang
authors.affiliation: School of science, Linyi University, Linyi 276005, P. R. China.
authors.forename: Jianfu
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Physics, Yancheng Institute of Technology, Yancheng 224051, China.
authors.forename: Ning
authors.initials: N
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012, P. R. China.
authors.forename: Hongyang
authors.initials: H
authors.lastname: Zhu
authors.affiliation: Beijing Computational Science Research Center, Beijing, 100084, P. R. China.
authors.forename: Ziyu
authors.initials: Z
authors.lastname: Hu
authors.affiliation: Institute of Condensed Matter Physics, Linyi University, Linyi 276005, P. R. China.
authors.forename: Li
authors.initials: L
authors.lastname: Chen