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Electronic structure and magnetism for FeSi$_{(1-x)}$Ge$_x$ from supercell calculations

T. Jarlborg
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Abstract

Recent studies of FeSi$_{(1-x)}$Ge$_x$, which found a transition from an insulating to a magnetic metallic state near $x$=0.25, have revived the discussion about the role of strong correlation in these systems. Here are spin polarized band calculations made for 64-atom supercells of FeSi$_{(1-x)}$Ge$_x$ for different $x$ and different volumes for large $x$. The results show that the small band gap in FeSi is closed for $x \geq 0.3$, because of both substitutional disorder and increased volume. Ferromagnetism appears near this composition and becomes enforced for increasing $x$. The $x$-dependence of the electronic specific heat can be understood from the exchange splitting of the density-of-states near the gap. Strong volume dependencies for the properties of FeGe suggest experiments using pressure instead of $x$ for investigations of the gap.

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T. Jarlborg. 2004-04-01. Electronic structure and magnetism for FeSi$_{(1-x)}$Ge$_x$ from supercell calculations. https://doi.org/10.1016/j.jmmm.2004.05.028

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