Long-range supercurrents through a chiral non-collinear antiferromagnet in lateral Josephson junctions

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Phenomena

Background:

• Proximity-coupling chiral non-collinear antiferromagnets (AFMs) with superconductors converts singlet Cooper pairs to spin-polarized triplet pairs.
• This conversion enables non-dissipative, long-range spin correlations via fictitious magnetic fields from Berry phase in AFMs.

Purpose of the Study:

• To investigate long-range Josephson supercurrents in epitaxial thin films of the chiral antiferromagnet Mn3Ge.
• To explore the potential of chiral AFMs for generating spin-polarized triplet pairs.

Main Methods:

• Fabrication of epitaxial thin films of Mn3Ge.
• Measurement of lateral Josephson supercurrents.
• Analysis of supercurrent decay and response to external magnetic fields.
• Comparison with collinear antiferromagnets like IrMn.

Main Results:

• Observed long-ranged lateral Josephson supercurrents through Mn3Ge.
• Supercurrents decayed significantly slower than expected for singlet pair correlations.
• Supercurrents exhibited spatial quantum interference in response to magnetic fields.
• Long-range supercurrents were present in both single- and mixed-phase Mn3Ge but absent in IrMn.

Conclusions:

• Chiral AFM Mn3Ge supports long-range Josephson supercurrents, demonstrating efficient conversion to spin-polarized triplet pairs.
• The findings suggest a pathway for topological generation of spin-polarized triplet pairs using Berry phase engineering in chiral AFMs.