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arXiv · 0906.1408

K$_2$Cr$_8$O$_{16}$ predicted as a half-metallic ferromagnet: Scenario for a metal-insulator transition

M. Sakamaki·T. Konishi·Y. Ohta
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Abstract

Based on the first-principles electronic structure calculations, we predict that a chromium oxide K$_2$Cr$_8$O$_{16}$ of hollandite type should be a half-metallic ferromagnet where the Fermi level crosses only the majority-spin band, whereas the minority-spin band has a semiconducting gap. We show that the double-exchange mechanism is responsible for the observed saturated ferromagnetism. We discuss possible scenarios of the metal-insulator transition observed at low temperature and we argue that the formation of the incommensurate, long-wavelength density wave of spinless fermions caused by the Fermi-surface nesting may be the origin of the opening of the charge gap.

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M. Sakamaki, T. Konishi, Y. Ohta. 2009-06-29. K$_2$Cr$_8$O$_{16}$ predicted as a half-metallic ferromagnet: Scenario for a metal-insulator transition. https://doi.org/10.1103/physrevb.80.024416

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