Spin waves in disordered materials.

Area of Science:

• Condensed Matter Physics
• Materials Science
• Computational Physics

Background:

• Studying spin waves (magnons) in disordered magnetic materials is crucial for understanding their magnetic properties.
• Existing methods often struggle with arbitrary disorder types and concentrations.
• Accurate theoretical models are needed for designing novel magnetic materials.

Purpose of the Study:

• To present an efficient and versatile methodology for calculating magnon properties in disordered spin systems.
• To enable the study of arbitrary disorder types and concentrations in magnetic materials.
• To provide an ab initio approach for predicting magnon behavior in real materials.

Main Methods:

• Utilizing a Heisenberg model for spin systems with disorder.
• Employing a single-site coherent potential approximation for substitutional disorder.
• Performing direct numerical simulations of large supercells with configurational averaging for arbitrary disorder.
• Deriving effective interactions from first-principles using self-consistent Green function methods within density functional theory.

Main Results:

• The proposed methodology efficiently calculates magnon properties across all concentrations and wave vectors for substitutional disorder.
• The approach is computationally inexpensive and directly applicable to alloys and doped materials.
• The method is versatile, handling arbitrary disorder types through supercell simulations.

Conclusions:

• The developed methodology offers an efficient and accurate way to study spin waves in a wide range of disordered magnetic materials.
• This ab initio approach bridges the gap between theoretical models and experimental observations in real materials.
• The findings pave the way for the rational design of magnetic materials with tailored spin wave properties.