First-principles study of CaFe2As2 under pressure

Article

关键词: GENERALIZED GRADIENT APPROXIMATION;    AUGMENTED-WAVE METHOD;    DYNAMICS;   

DOI  :  10.1103/PhysRevB.88.045117

来源: SCIE

【 摘 要 】

We perform first-principles calculations on CaFe2As2 under hydrostatic pressure. Our total-energy calculations show that though the striped antiferromagnetic (AFM) orthorhombic (OR) phase is favored at P = 0, a nonmagnetic collapsed tetragonal (cT) phase with diminished c parameter is favored for P > 0.36 GPa, in agreement with experiments. Rather than a mechanical instability, this is an enthalpically driven transition from the higher volume OR phase to the lower volume cT phase. A simple thermodynamic model provides an interpretation of the finite-temperature phase boundaries of the cT phase. Calculations of electronic density of states reveal pseudogaps in both OR and cT phases. Band-structure analysis provides insight into the origin of the pseudogaps while revealing the location and nature of hybridized Fe-d and As-p bonding orbitals.

【 授权许可】

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