Magnon spectra of multi-sublattice compounds from first principles

Area of Science:

• Condensed matter physics
• Materials science
• Quantum magnetism

Background:

• Understanding spin-wave excitations is crucial for developing advanced magnetic materials.
• Existing models often struggle with complex multi-sublattice magnetic systems.
• Accurate theoretical predictions are needed for designing materials with specific magnetic properties.

Purpose of the Study:

• To develop a systematic theoretical framework for investigating zero-temperature magnon spectra in collinear multi-sublattice magnetic systems.
• To apply this framework to Heusler compounds and evaluate their spin-wave parameters.
• To provide a method for capturing diverse magnetic behaviors, from ferromagnetic to antiferromagnetic dynamics.

Main Methods:

• Utilizing the Holstein-Primakoff formalism for magnon analysis.
• Modeling itinerant magnetism from first principles using density functional theory.
• Deriving exchange parameters to calculate the magnon dynamical matrix, group velocity, and spin-wave stiffness.

Main Results:

• Developed a theoretical framework yielding expressions for key spin-wave parameters.
• Successfully applied the formalism to ferrimagnetic Mn2CoAl, ferromagnetic Co2MnSi, and ferrimagnetic Mn2LiAl.
• Captured a range of magnetic behaviors, including parabolic ferromagnetic and linear antiferromagnetic dispersions.

Conclusions:

• The developed formalism offers a systematic approach for evaluating spin-wave parameters in complex magnetic systems.
• This work provides a valuable tool for predicting and understanding magnetic properties of Heusler compounds.
• The framework's ability to handle diverse magnetic dynamics enhances its applicability in materials design.