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0-pi transitions in Josephson junctions with antiferromagnetic interlayers
Brian M Andersen1, I V Bobkova, P J Hirschfeld
1Department of Physics, University of Florida, Gainesville, Florida 32611-8440, USA.
Physical Review Letters
|April 12, 2006
Summary
Superconductor-antiferromagnet-superconductor junctions show atomic-scale thickness dependence. The Josephson current is 0 or pi based on even/odd antiferromagnetic layers, with temperature-driven transitions in odd layers.
Area of Science:
- Condensed Matter Physics
- Superconductivity
- Spintronics
Background:
- Superconductor-antiferromagnet-superconductor (S-AF-S) junctions are crucial for understanding exotic superconducting states.
- The Josephson current in these junctions is sensitive to magnetic ordering in the antiferromagnetic (AF) layer.
Purpose of the Study:
- To investigate the atomic-scale dependence of the dc Josephson current on interlayer thickness in S-AF-S junctions.
- To elucidate the role of antiferromagnetic layer symmetry and spin-split Andreev bound states in determining junction properties.
Main Methods:
- Theoretical modeling of dc Josephson current in S-AF-S junctions.
- Analysis of the influence of interlayer thickness and antiferromagnetic ordering on superconducting correlations.
Main Results:
- The dc Josephson current exhibits a distinct atomic-scale dependence on the AF interlayer thickness.
- Junctions with even AF layers are 0 junctions, while those with odd AF layers are pi junctions at low temperatures.
- A temperature-induced pi-0 transition occurs in junctions with odd AF layers due to spin-split Andreev bound states.
Conclusions:
- The symmetry of the antiferromagnetic interlayer dictates the ground state (0 or pi) of the Josephson current.
- Spin-split Andreev bound states provide a mechanism for temperature-dependent phase transitions in S-AF-S junctions.
- Theoretical findings offer guidance for experimental realization and manipulation of Josephson currents in S-AF-S systems.