Linear spin wave theory for single-Q incommensurate magnetic structures

Area of Science:

• Condensed Matter Physics
• Materials Science

Background:

• Linear spin wave theory is crucial for understanding magnetic excitation spectra in ordered systems.
• The Holstein-Primakoff approximation is commonly used but has limitations for complex magnetic structures.

Purpose of the Study:

• To develop an algorithm for calculating spin wave spectra in magnetic systems with complex ordering.
• To extend linear spin wave theory to handle general moment directions and incommensurate structures.

Main Methods:

• Utilizing the Holstein-Primakoff approximation for spin operators.
• Implementing local coordinate transformations for individual spins.
• Applying rotating coordinate transformations to capture incommensurability.

Main Results:

• The proposed algorithm successfully calculates excitation spectra for systems with general magnetic ground states.
• The model accurately determines spin wave spectra in magnetic C-site langasites exhibiting incommensurate order.

Conclusions:

• The developed algorithm enhances the applicability of linear spin wave theory to more complex magnetic materials.
• This work provides a robust method for investigating spin dynamics in incommensurate magnetic systems.