Planar Hall Effect in Antiferromagnetic MnTe Thin Films.

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Mechanics

Background:

• Spin-orbit coupling (SOC) is crucial for understanding electronic properties in magnetic materials.
• Antiferromagnetic materials like α-MnTe exhibit complex electronic structures influenced by SOC.
• The planar Hall effect (PHE) is a sensitive probe of electronic band structure anisotropy.

Purpose of the Study:

• To investigate the impact of spin-orbit coupling on the electronic and transport properties of α-MnTe.
• To develop a theoretical model explaining the observed anisotropic band splitting and PHE.
• To quantify the PHE in α-MnTe thin films.

Main Methods:

• Ab initio calculations were performed to determine the electronic band structure.
• A minimal k·p model was constructed using group theory analysis and tight-binding methods.
• The model was validated by comparing its predictions to experimental phenomena like the zero-field PHE.

Main Results:

• Spin-orbit coupling in α-MnTe induces anisotropic valence-band splitting near the Γ point.
• This splitting results in four distinct spin-polarized electronic pockets.
• The developed k·p model accurately describes the rotation symmetry of the zero-field PHE.
• The PHE is quantitatively estimated to be 25%-31% in ideal α-MnTe thin films with a single antiferromagnetic domain.

Conclusions:

• Spin-orbit coupling is the primary mechanism behind the anisotropic band structure and PHE in α-MnTe.
• The theoretical model provides a robust framework for understanding SOC-driven transport phenomena in this material.
• The significant PHE in α-MnTe suggests potential applications in spintronic devices.