Band structure induced electronic correlations in nickel and iron: van-Hove singularities vs. Earth's core conditions

ORAL

Abstract

Some Bravais lattices have a particular geometry and can slow down the motion of Bloch electrons: a 'pre-localisation' due to band structure properties. Another known source of electronic localisation in solids is the Coulomb repulsion in partially-filled d- or f-orbitals, which leads to the formation of local magnetic moments. The combination of these two effects has been viewed so far as mainly an academic issue. Here we show with ab-initio calculations of unprecedented accuracy and model studies, that their synergy represents instead the underlying physical mechanism in two of the most important ferromagnets: nickel and iron. Furthermore in nickel, the van-Hove singularity is essential for ferromagnetism to appear. Nickel's electron-electron scattering rate is linear in temperature, in violation of the conventional Landau theory of metals. This is true even at Earth's-core conditions, at which iron is instead a good Fermi-liquid. The importance of nickel in models of geomagnetism may therefore be reconsidered.

*Funding by DFG projects FOR 1346, FOR 1162 and SFB 1170 ‘ToCoTronics’. The computation time was provided by the Leibniz Supercomputing Centre on the GCS Supercomputer SuperMUC (LRZ, www.lrz.de).

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Presenters

  • Andreas Hausoel

    • University of Würzburg
    • Department for theoretical physics, University of Wuerzburg, Germany

Authors

  • Andreas Hausoel

    • University of Würzburg
    • Department for theoretical physics, University of Wuerzburg, Germany

  • Michael Karolak

    • Department for theoretical physics, University of Wuerzburg, Germany

  • Ersoy Sasioglu

    • Institute for Physics, University of Halle, Germany

  • Alexander I. Lichtenstein

    • University of Hamburg
    • Institute for theoretical physics, University of Hamburg, Germany

  • Karsten Held

    • Institut für Festkörper Physik, TU Wien
    • Institute of Solid State Physics, TU Wien
    • Institute for Solid State Physics, TU Wien
    • TU Wien
    • Institute of Solid State Physics, TU Vienna, Austria

  • Andrey A. Katanin

    • Institute of Metal Physics, Ekaterinburg
    • Ural Federal University Ekaterinburg, Russia

  • Alessandro Toschi

    • Institute of Solid State Physics, TU Wien
    • TU Wien
    • TU Vienna
    • Institute of Solid State Physics, TU Vienna, Austria

  • Giorgio Sangiovanni

    • University of Würzburg
    • University of Wurzburg
    • Department for theoretical physics, University of Wuerzburg, Germany