Premium
Macroscopic and Microscopic Structures of Cesium Lead Iodide Perovskite from Atomistic Simulations
Author(s) -
Chen Lan,
Xu Bin,
Yang Yurong,
Bellaiche Laurent
Publication year - 2020
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201909496
Subject(s) - orthorhombic crystal system , materials science , perovskite (structure) , octahedron , tetragonal crystal system , hamiltonian (control theory) , condensed matter physics , halide , phase (matter) , phase transition , iodide , thermodynamics , crystallography , crystal structure , physics , chemistry , quantum mechanics , inorganic chemistry , mathematical optimization , mathematics , organic chemistry
A first‐principles‐based effective Hamiltonian is developed and employed to investigate finite‐temperature structural properties of a prototype of perovskite halides, that is CsPbI 3 . Such simulations, when using first‐principles‐extracted coefficients, successfully reproduce the existence of an orthorhombic Pnma state and its iodine octahedral tilting angles around room temperature. However, they also yield a direct transformation from Pnma to cubic P m 3 ¯ m upon heating, unlike measurements that reported the occurrence of an intermediate long‐range‐tilted tetragonal P4/mbm phase in‐between the orthorhombic and cubic phases. Such disagreement, which may cast some doubts about the extent to which first‐principle methods can be trusted to mimic hybrid perovskites, can be resolved by “only” changing one short‐range tilting parameter in the whole set of effective Hamiltonian coefficients. In such a case, some reasonable values of this specific parameter result in the predictions that i) the intermediate P4/mbm state originates from fluctuations over many different tilted states; and ii) the cubic P m 3 ¯ m phase is highly locally distorted and develops strong transverse antiphase correlation between first‐nearest neighbor iodine octahedral tiltings, before undergoing a phase transition to P4/mbm under cooling.