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Mechanical and chemical pressure effects on the AeFe 2 As 2 (Ae = Ba, Sr, Ca) compounds: Density functional theory

Aghajani, M ; Sharif University of Technology | 2019

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  1. Type of Document: Article
  2. DOI: 10.1016/j.commatsci.2019.01.021
  3. Publisher: Elsevier B.V , 2019
  4. Abstract:
  5. We have studied the pressure-induced structural, magnetic and electronic properties of AeFe 2 As 2 (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 BaFe 2 As 2 have been investigated. We have found a magnetic transition at the same primitive unit cell volume, around 81 Å 3 for the (Ba⧹Ca)Fe 2 As 2 compounds, which predicts a magnetic transition pressure of 12 GPa for SrFe 2 As 2 . The structural parameters of FeAs 4 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
  6. Keywords:
  7. 122 iron-pnictide compounds ; BaFe 2 As 2 ; Chemical and mechanical pressure effects ; First-principle calculations ; Barium compounds ; Calcium compounds ; Charge transfer ; Density functional theory ; Electronic properties ; Magnetism ; Pressure effects ; Strontium compounds ; BaFe2As2 ; Chemical pressure effects ; First principle calculations ; Hole and electron pockets ; Iron-pnictide ; Magnetic and electronic properties ; Mechanical pressure ; Pressure induced charge transfers ; Iron compounds
  8. Source: Computational Materials Science ; Volume 160 , 2019 , Pages 233-244 ; 09270256 (ISSN)
  9. URL: https://www.sciencedirect.com/science/article/abs/pii/S0927025619300230