Determining the anisotropic exchange coupling of CrO2 via first-principles density functional theory calculations

Hunter Sims, Shawn J. Oset, William H. Butler, James M. MacLaren, Martijn Marsman

Veröffentlichungen: Beitrag in FachzeitschriftArtikelPeer Reviewed

Abstract

We report a study of the anisotropic exchange interactions in bulk CrO2 calculated from first principles within density functional theory (DFT) [W. Kohn and L. J. Sham, Phys. Rev. 140, A1133 (1965)]. We determine the exchange coupling energies, using both the experimental lattice parameters and those obtained within DFT, within a modified Heisenberg model Hamiltonian in two ways. We employ a supercell method in which certain spins within a cell are rotated and the energy dependence is calculated and a spin-spiral method that modifies the periodic boundary conditions of the problem to allow for an overall rotation of the spins between unit cells. Using the results from each of these methods, we calculate the spin-wave stiffness constant D from the exchange energies using the magnon dispersion relation. We employ a Monte Carlo method to determine the DFT-predicted Curie temperature from these calculated energies and compare with accepted values. Finally, we offer an evaluation of the accuracy of the DFT-based methods and suggest implications of the competing ferromagnetic and antiferromagnetic interactions.
OriginalspracheEnglisch
Aufsatznummer224436
Seitenumfang9
FachzeitschriftPhysical Review B
Jahrgang81
Ausgabenummer22
DOIs
PublikationsstatusVeröffentlicht - 2010

ÖFOS 2012

  • 103018 Materialphysik

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