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Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses
Published on: June 7, 2018
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Time-Dependent Magnons from First Principles
N Tancogne-Dejean1, F G Eich1, A Rubio1,2,3,4
1Max Planck Institute for the Structure and Dynamics of Matter , Luruper Chaussee 149 , 22761 Hamburg , Germany.
Journal of Chemical Theory and Computation
|January 11, 2020
Summary
We developed a new method to calculate magnetic excitations in materials using time-dependent density functional theory. This approach simulates magnetic dynamics and reveals excitation spectra, including nonlinear effects.
Area of Science:
- Condensed Matter Physics
- Quantum Mechanics
- Materials Science
Background:
- Understanding magnetic excitations is crucial for developing advanced magnetic materials.
- Existing methods often rely on linear-response approximations, limiting their scope.
Purpose of the Study:
- To introduce an efficient, non-perturbative computational scheme for magnetic excitations in extended systems.
- To extend the capabilities of time-dependent density functional theory (TDDFT) for magnetic dynamics.
Main Methods:
- Employing TDDFT with real-time propagation of Kohn-Sham equations.
- Applying an ultrashort magnetic pulse to perturb the system from equilibrium.
- Analyzing time-dependent magnetization to determine the excitation spectrum.
Main Results:
- Successfully computed magnetic excitation spectra for iron, cobalt, and nickel.
- Demonstrated the method's accuracy by comparing results with linear-response TDDFT.
- Presented the first ab initio calculations of nonlinear magnetic excitations in iron.
Conclusions:
- The proposed real-time TDDFT approach offers an efficient and versatile tool for studying magnetic excitations.
- This method goes beyond linear-response, enabling the investigation of nonlinear magnetic phenomena.
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