Mechanical and chemical pressure effects on the AeFe2As2 (Ae = Ba, Sr, Ca) compounds: Density functional theory AITranslate

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DOI：https://doi.org/10.1016/j.commatsci.2019.01.021

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Highlights • Chemical and mechanical pressure effects in (Ba ⧹ Sr ⧹ Ca)Fe2As2 are investigated. • Magnetic transition is predicted to occur about 12 GPa for the SrFe2As2 compound. • Pressure-induced charge transfer demonstrates an effective hole doping. • Changes of DOS and band structure by pressure are investigated. • Fermi surface topologies are presented in different pressures. We have studied the pressure-induced structural, magnetic and electronic properties of AeFe2As2 (Ae = Ba, Sr, Ca) compounds in the framework of density functional theory within the GGA-PBE method. The effects of chemical pressure generated by Sr and Ca substitutions in BaFe2As2 have been investigated. We have found a magnetic transition at the same primitive unit cell volume, around 81 Å3 for the (Ba ⧹ Ca)Fe2As2 compounds, which predicts a magnetic transition pressure of 12 GPa for SrFe2As2. The structural parameters of FeAs4 tetrahedra are obtained after ionic relaxation and compared with the existing experimental results. The change of these internal parameters is ascribed to pressure-induced charge transfer, i.e., as the As-Ae bonds absorb electrons, the Fe-As bonds are depleted, and thus the number of holes in the Fe-As layers increases. The changes of the density of states, the band structure and the hole- and electron- pockets of Fermi surface by pressure have been discussed. Graphical abstract Download : Download high-res image (383KB) Download : Download full-size image