Chiral Split Magnon in Altermagnetic MnTe.

Area of Science:

• Condensed Matter Physics
• Materials Science
• Magnetism

Background:

• Altermagnetism is a novel magnetic state characterized by alternating spin polarization in real and reciprocal space.
• Theoretical predictions suggest that altermagnets should exhibit alternating chiral splitting in their magnon bands, analogous to electronic band splitting.

Purpose of the Study:

• To experimentally verify the predicted alternating chiral splitting of magnon bands in altermagnets.
• To investigate the underlying physical mechanisms responsible for the observed magnon splitting.
• To identify other magnetic properties present in the studied material, MnTe.

Main Methods:

• Inelastic neutron scattering experiments were conducted on α-MnTe to probe magnon excitations.
• Analysis of the scattering data allowed for the direct observation of magnon band splitting.
• A spin-wave model was developed and utilized for further theoretical calculations.

Main Results:

• Direct experimental evidence of altermagnetic magnon splitting was observed in α-MnTe.
• The lifted degeneracy of magnons was successfully explained by a symmetric-exchange interaction.
• Calculations confirmed that the magnons exhibit chiral splitting, consistent with altermagnetic theory.
• The presence of g-wave magnetism in MnTe was experimentally identified.

Conclusions:

• The study provides the first direct experimental observation of altermagnetic magnon splitting.
• The findings validate theoretical predictions of chiral splitting in altermagnetic magnon bands.
• The identification of g-wave magnetism in MnTe further characterizes its unique magnetic properties.