The Einstein-de Haas effect in an Fe₁₅cluster.

Area of Science:

• Condensed Matter Physics
• Quantum Mechanics
• Materials Science

Background:

• Classical spin-lattice coupling models fail to accurately predict ferromagnetic material properties like heat transport and magnetic moment collapse.
• These limitations stem from the inadequate treatment of quantum mechanical effects, particularly spin-orbit coupling (SOC).

Purpose of the Study:

• To introduce a novel time-dependent, non-collinear tight binding model incorporating SOC and vector Stoner exchange.
• To simulate the Einstein-de Haas (EdH) effect in a ferromagnetic iron (Fe₁₅) cluster using this advanced model.
• To investigate the role of SOC in angular momentum transfer between electrons and nuclei.

Main Methods:

• Development and application of a time-dependent, non-collinear tight binding model.
• Inclusion of spin-orbit coupling (SOC) and vector Stoner exchange terms.
• Simulation of the Einstein-de Haas (EdH) effect in a Fe₁₅ cluster under an external magnetic field.

Main Results:

• The model successfully simulates the Einstein-de Haas (EdH) effect from first principles in an Fe cluster.
• Adiabaticity timescales governing the response of angular momenta to magnetic fields were investigated.
• Spin-orbit coupling (SOC) was identified as essential for observing electron-to-nucleus angular momentum transfer at realistic magnetic field strengths.

Conclusions:

• The developed tight binding model provides an accurate framework for studying quantum effects in ferromagnetic materials.
• The findings highlight the critical role of spin-orbit coupling in phenomena like the Einstein-de Haas effect.
• This work offers a first-principles simulation of the EdH effect, advancing the understanding of magnetic materials.