How much anisotropy is enough? LDA+U study of anisotropic magnetic interactions in iridium oxide

Datum

20.04.2023

Zeit

13:00 - 14:00

Sprecher

Alexander Yaresko

Zugehörigkeit

Max Planck Institute for Solid State Research

Sprache

en

Hauptthema

Materialien

Host

Dr. Silvia Seiro

Beschreibung

Because of strong spin-orbit coupling of Iridium 5d electrons magnetic interaction in many Ir4+ oxides cannot be described by an isotropic Heisenberg-like model and anisotropic exchange interactions become important. In this work LSDA+U band structure calculations with constrained magnetization direction are used to study magnetic properties of some Ir oxides with edge- and corner-sharing IrO octahedra. Effective magnetic interactions are estimated by mapping calculated total energy differences onto appropriate effective models which include isotropic Heisenberg as well as bond-dependent anisotropic interactions. In Na2IrO3, with edge sharing IrO octahedra forming a honeycomb lattice, magnetic interactions are dominated by the symmetric anisotropic Kitaev term. In R2Ir2O7 iridates, with a pyrochlore crystal structure, nearest neighbor Ir-Ir bonds do not have inversion symmetry and antisymmetric Dzyaloshinskii-Moriya (DM) interaction is allowed. It stabilizes noncollinear all-in-all-out magnetic order in pyrochlore iridates with a small radius of a rear-earth ion R.

Links

• Seminars at the IFW

Letztmalig verändert: 20.04.2023, 07:39:52