Parameterization of magnetic vector potentials and fields for efficient multislice calculations of elastic electron...

Area of Science:

• Materials Science
• Computational Physics
• Solid State Physics

Background:

• The multislice method is essential for analyzing electron scattering in crystals.
• Incorporating magnetic effects is vital for understanding vortex beams and magnetic materials.
• Simulating magnetism in large systems presents computational challenges for the multislice method.

Purpose of the Study:

• To develop an efficient method for computing magnetic vector potentials (A) and magnetic fields (B) in large crystal simulations.
• To introduce and validate parameterized magnetic (PM) values for transition metal elements.
• To assess the accuracy of the PM approach compared to direct density functional theory (DFT) calculations.

Main Methods:

• Atomic density functional theory (DFT) calculations were used to derive parameterized magnetic (PM) values for transition metals.
• The multislice method was employed to simulate electron wavefunction propagation.
• PM values were tested against direct DFT calculations for ferromagnetic body-centred cubic (b.c.c.) Fe and tetragonal FePt.

Main Results:

• Parameterized magnetic (PM) values enable efficient computation of approximate magnetic vector potentials (A) and magnetic fields (B).
• The PM approach accurately describes magnetic fields in b.c.c. Fe.
• For FePt, the PM approach shows slightly reduced accuracy due to spin density deformations but still captures magnetic effects well.
• Calculations of diffraction pattern intensity changes confirm the PM approach's ability to describe magnetism in these systems.

Conclusions:

• Parameterized magnetic (PM) values offer an efficient and accurate method for incorporating magnetic effects into multislice simulations.
• This approach facilitates the study of magnetic interactions in larger and more complex magnetic materials.
• The PM method provides a valuable tool for analyzing magnetic Bragg spots and magnon signatures.