Berlin 2024 – scientific programme
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MA: Fachverband Magnetismus
MA 10: Electron Theory of Magnetism and Correlations/Other Theory
MA 10.2: Talk
Monday, March 18, 2024, 15:15–15:30, EB 107
Exploring Temperature-Dependent Magnetic Properties in NiO: A First Principles Study — •Ravi Kaushik1,2, Ryota Ono3, and Sergey Artyukhin1 — 1Italian Institute of Technology, Genova 16163, Italy — 2University of Genova. Genova, Italy — 3National Institute for Materials Science, Ibaraki, Japan
Knowing the magnetic Hamiltonian parameters, such as Heisenberg exchange constants, is crucial for describing magnetic properties of materials. Such parameters can be efficiently calculated using Density Functional Theory, which operates at T=0. Magnetic materials exhibit a complex interplay between spin, orbital, and lattice degrees of freedom, and magnetic exchange interactions are influenced by thermally excited phonons. Here we develop a method to compute the change in exchange constants with temperature, and test it on a paradigm antiferromagnet, NiO. Our approach is based on a special displacement method, which should be modified to use two specific configurations with opposite displacements, to average out the exchange contribution, linear in phonon amplitude. The results enable the calculation of magnetic exchange constants and modelling of magnetic systems, at finite temperatures and set the stage for more intricate studies in systems with complex interdependencies.
Keywords: Density Functional Theory; Heisenberg Exchange; Temperature Dependence; Spin Lattice Coupling