Pressure- and temperature-induced structural phase transitions of CaFe2As2and BaFe2As2studied in the Hund’s rule correlation picture

2010/07/27 by Wei Ji, Xun-Wang Yan, Zhong-Yi Lu
Chemistry · Materials Science · Physics and Astronomy · #Computer science #Inorganic Chemistry and Materials #Iron-based superconductors research #Phase (matter) #Physics #Rare-earth and actinide compounds #cond-mat.mtrl-sci

paper · pdf · doi:10.1103/physrevb.83.132504

published as Phys. Rev. B 83, 132504 (2011) · 5 pages and 4 figures

arxiv created 2010/07/27 · openalex publication_date 2011/04/13 · arxiv updated 2011/04/28 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05

Abstract

With the proposed Hund's rule correlation picture, i.e., the fluctuating Fe local moments with the As-bridged antiferromagnetic superexchange interactions, the exceptional collapsed tetragonal phase and related phase transitions observed in CaFe₂As₂ are well understood. Within the same framework, a pressure-temperature phase diagram is predicted for BaFe₂As₂ as well, in which a paramagnetic tetragonal structure and a collinear antiferromagnetic orthorhombic structure to nonmagnetic tetragonal structure transitions take place around 4--8 GPa and 10--15 GPa, respectively, and a nonmagnetic tetragonal to a nonmagnetic collapsed tetragonal structure transition takes place over 26 GPa. Our study helps to better understand the complex correlation among crystal structure, magnetism, and electronic structure in pnictides, a precondition to understanding the superconductivity in pnictides.

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