title: New insight into the structural evolution of PbTiO3: an unbiased structure search.
abstract: Understanding the structural evolution of materials is a challenging problem of condensed matter physics. Solving this problem would open new ways for understanding the behaviors of materials. In this context, we here report unbiased structure searches for a prototypical perovskite oxide, PbTiO3, based on the CALYPSO (Crystal structure AnaLYsis by Particle Swarm Optimization) method in conjunction with first-principles calculations. For the first time, we decipher the structure evolution of PbTiO3from a zero dimensional (0D) cluster to a two dimensional (2D) layered structure and in the end to a three dimensional (3D) bulk solid. Our unbiased structure search is successful in reproducing the cubic Pm3[combining macron]m and tetragonal P4mm phases of PbTiO3at ambient pressure. We also predict a new quasi-planar kite shape structure of the PbTiO3cluster, with Cssymmetry and a surprisingly large HOMO-LUMO gap. Furthermore, by using this method, we predict that the 2D planar PbTiO3monolayer is unstable in the perpendicular direction and the 2D PbTiO3double layer is dynamically stable, with a hope that it can provide guidance to future synthesis of low dimensional perovskite oxides.
authors.affiliation: Department of Physics, Nanyang Normal University, Nanyang 473061, China. lucheng@calypso.cn and Department of Physics and High Pressure Science and Engineering Center, University of Nevada, Las Vegas, Nevada 89154, USA and Computational Astrophysics Laboratory, RIKEN (The Institute of Physical and Chemical Research), 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
authors.forename: Cheng
authors.identifier: http://orcid.org/0000-0003-1746-7697
authors.initials: C
authors.lastname: Lu
authors.affiliation: Department of Physics, Nanyang Normal University, Nanyang 473061, China. lucheng@calypso.cn and Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China.
authors.forename: Jingjing
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Physics, Nanyang Normal University, Nanyang 473061, China. lucheng@calypso.cn.
authors.forename: Ping
authors.initials: P
authors.lastname: Wang
authors.affiliation: Department of Physics, Nanyang Normal University, Nanyang 473061, China. lucheng@calypso.cn and Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China.
authors.forename: Xinxin
authors.initials: X
authors.lastname: Xia
authors.affiliation: Department of Physics, Nanyang Normal University, Nanyang 473061, China. lucheng@calypso.cn and Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China.
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Jin
authors.affiliation: College of Physics and Electronic Information, Inner Mongolia University for the Nationalities, Tongliao 028043, China.
authors.forename: Peifang
authors.initials: P
authors.lastname: Li
authors.affiliation: College of Physics and Electronic Information, Inner Mongolia University for the Nationalities, Tongliao 028043, China.
authors.forename: Gang
authors.initials: G
authors.lastname: Bao