High Pressure Driven Isostructural Electronic Phase Separation in 2D BiOI. Issue 6 (21st February 2019)

• Record Type: Journal Article
• Authors: Xu, Zhongfei; Li, Hui; Hu, Shuxian; Zhuang, Jincheng; Du, Yi; Hao, Weichang
• Is Part Of: Physica status solidi. Volume 13:Issue 6(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-02-21
• Subjects: 2D‐layered BiOl -- electronic phase separation -- first‐principles calculations -- pressure‐induced properties; Solid state physics -- Periodicals; 530.4105
• DOI: 10.1002/pssr.201800650
• Languages: English
• ISSNs: 1862-6254

Abstract

Abstract : 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‐pz 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 the I ‐ d x 2 – y 2 energy 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. Abstract : The pressure‐induced unique physical properties of materials have been increasingly explored to access a wealth of phenomena such as superconductivity, the insulator–metal transformation, phase separation. Here, the authors found that BiOI undergoes different transformations in the pressure range of 0–160 GPa. Isostructural electronic phase separation is observed at 160 GPa, where the I–I layer displays a metallic state.