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High Pressure Driven Isostructural Electronic Phase Separation in 2D BiOI
Author(s) -
Xu Zhongfei,
Li Hui,
Hu Shuxian,
Zhuang Jincheng,
Du Yi,
Hao Weichang
Publication year - 2019
Publication title -
physica status solidi (rrl) – rapid research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.786
H-Index - 68
eISSN - 1862-6270
pISSN - 1862-6254
DOI - 10.1002/pssr.201800650
Subject(s) - isostructural , orthorhombic crystal system , van der waals force , tetragonal crystal system , crystallography , materials science , phase (matter) , fermi level , lone pair , monoclinic crystal system , covalent bond , semiconductor , chemistry , condensed matter physics , chemical physics , crystal structure , molecule , physics , organic chemistry , quantum mechanics , electron , optoelectronics
The crystal structures of BiOI under different pressures are predicted, in which the phase transformation from tetragonal BiOI into orthorhombic BiOI is observed at 100 GPa due to the appearance of Bi–I bonds (Bi‐6s 2 lone pair and I‐p z obital) between interlayer Bi and I atoms. Most interestingly, for orthorhombic BiOI, an isostructural electronic phase separation is observed at 160 GPa. The electronic structure of BiOI separates into semiconductor state (contributed by intralayer O–Bi–O) and metal state, which originate from the interlayer I–I bonds. More specifically, conversion from interlayer Bi–I interaction to interlayer I–I interaction under higher pressure, results in the continuous decline of theI ‐ dx 2 – y 2energy band, which then crosses the Fermi‐level. In comparison, the O–Bi–O layer shows almost no change, owing to its strong covalent bonds. These results demonstrate that the dramatic variation of the interaction between the van der Waals layers can lead to the metallic iodine character in BiOI.