On the origin of magnetic anisotropy in two dimensional CrI3

Research output: Contribution to journalArticleScientificpeer-review

Researchers

Research units

  • International Iberian Nanotechnology Laboratory
  • University of Alicante

Abstract

The observation of ferromagnetic order in a monolayer of CrI3 has been recently reported, with a Curie temperature of 45 K and off-plane easy axis. Here we study the origin of magnetic anisotropy, a necessary ingredient to have magnetic order in two dimensions, combining two levels of modeling, density functional calculations and spin model Hamiltonians. We find two different contributions to the magnetic anisotropy of the material, favoring off-plane magnetization and opening a gap in the spin wave spectrum. First, ferromagnetic super-exchange across the ≃90 degree Cr–I–Cr bonds, are anisotropic, due to the spin–orbit interaction of the ligand I atoms. Second, a much smaller contribution that comes from the single ion anisotropy of the S = 3/2 Cr atom. Our results permit to establish the XXZ Hamiltonian, with a very small single ion anisotropy, as the adequate spin model for this system. Using spin wave theory we estimate the Curie temperature and we highlight the essential role played by the gap that magnetic anisotropy induces on the magnon spectrum.

Details

Original languageEnglish
Article number035002
Journal2D Materials
Volume4
Issue number3
Publication statusPublished - 1 Sep 2017
MoE publication typeA1 Journal article-refereed

    Research areas

  • Chromium iodine, Magnetic anisotropy, Magnetism, Spin wave

ID: 36719199