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A shortcut to gradient-corrected magnon dispersion: exchange-only case

  • Florian G. EichEmail author
  • Stefano Pittalis
  • Giovanni Vignale
Open Access
Regular Article
Part of the following topical collections:
  1. Topical issue: Special issue in honor of Hardy Gross

Abstract

Ab initio calculations of the magnon dispersion in ferromagnetic materials typically rely on the adiabatic local density approximation (ALDA) in which the effective exchange-correlation field is everywhere parallel to the magnetization. These calculations, however, tend to overestimate the “magnon stiffness”, defined as the curvature of the magnon frequency vs. wave vector relation evaluated at zero wave vector. Here we suggest a simple procedure to improve the magnon dispersion by taking into account gradient corrections to the ALDA at the exchange-only level. We find that this gradient correction always reduces the magnon stiffness. The surprisingly large size of these corrections (~30%) greatly improves the agreement between the calculated and the observed magnon stiffness for cobalt and nickel, which are known to be overestimated within the ALDA.

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Copyright information

© The Author(s) 2018

Open AccessThis is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Authors and Affiliations

  1. 1.Max Planck Institute for the Structure and Dynamics of MatterHamburgGermany
  2. 2.Istituto Nanoscienze, Consiglio Nazionale delle RicercheModenaItaly
  3. 3.Department of Physics and AstronomyUniversity of MissouriColumbiaUSA

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