First-principles evidence of Mn moment canting in hole-doped Ba$_{1-2x}$K$_{2x}$Mn$_{2}$As$_{2}$

J. K. Glasbrenner; I. I. Mazin

doi:10.1103/PhysRevB.89.060403

paper

First-principles evidence of Mn moment canting in hole-doped Ba $_{1 - 2 x}$ K $_{2 x}$ Mn $_{2}$ As $_{2}$

arXiv:1311.1537 · doi:10.1103/PhysRevB.89.060403

Abstract

The compound BaFe $_{2}$ As $_{2}$ is the proptotypical example of the 122 family of high- $T_{c}$ Fe-based superconductors that crystallize in the ThCr $_{2}$ Si $_{2}$ structure. Isostructural compounds can be formed by replacing Fe with another transition metal; using Mn produces the material BaMn $_{2}$ As $_{2}$ , which unlike its Fe-based cousin has an insulating ground state with a large magnetic moment of $3.9 μ_{B}$ and G-type antiferromagnetic order. Despite its lack of superconductivity, the material is interesting in its own right. Recent experimental studies have shown that hole-doping the compound by substituting K for Ba leads to metallic behavior and a spontaneous, weak, in-plane magnetization, which was attributed to the holes fully polarizing independent of the Mn moments, producing half-metallic behavior. However the observed in-plane magnetization can also be understood as a small canting of the Mn moments. Using density functional theory, we demonstrate that a Mn moment canting occurs upon hole-doping the compound. We argue that this is due to the competition between the super- and double exchange interactions, which we support using a simple tight-binding model of the superexchange-double exchange interaction and the Andersen Force Theorem. Our calculations also rule out an in-plane polarization of As holes as an explanation for the in-plane magnetization.

5 pages, 1 figure, submitted to Phys. Rev. B (Rapid Communications)

First-principles evidence of Mn moment canting in hole-doped Ba $_{1 - 2 x}$ K $_{2 x}$ Mn $_{2}$ As $_{2}$

Abstract

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First-principles evidence of Mn moment canting in hole-doped Ba1−2x​K2x​Mn2​As2​

Abstract

References in corpus (6)

Cited by in corpus (8)

First-principles evidence of Mn moment canting in hole-doped Ba $_{1 - 2 x}$ K $_{2 x}$ Mn $_{2}$ As $_{2}$