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Pairing symmetry conversion by spin-active interfaces in magnetic normal-metal-superconductor junctions.
Jacob Linder1, Takehito Yokoyama, Asle Sudbø
1Department of Physics, Norwegian University of Science and Technology, N-7491 Trondheim, Norway.
Physical Review Letters
|April 28, 2009
Summary
We found that a spin-active interface can suppress even-frequency superconductivity in normal metals, while preserving the odd-frequency component. This offers a new route to observe exotic superconducting phenomena.
Area of Science:
- Condensed Matter Physics
- Superconductivity
- Spintronics
Background:
- Proximity effects describe how superconducting properties can be induced in adjacent normal materials.
- Spin-active interfaces play a crucial role in mediating interactions between electron spins and material properties.
Purpose of the Study:
- To investigate the impact of spin-active interfaces on superconducting correlations in normal metals.
- To explore the conditions under which conventional even-frequency superconductivity is suppressed.
- To identify methods for observing unconventional odd-frequency superconducting components.
Main Methods:
- Theoretical modeling of superconducting correlations in a normal metal-superconductor junction.
- Analysis of the system's behavior under varying interface resistance and spin polarization.
- Focus on both ballistic and diffusive transport regimes in the normal metal.
Main Results:
- A critical interface resistance was identified, above which the even-frequency proximity effect vanishes at the chemical potential.
- The odd-frequency superconducting component was shown to remain finite even when the even-frequency component is suppressed.
- The results hold for any degree of interface spin polarization.
Conclusions:
- Spin-active interfaces offer a tunable mechanism to control superconducting correlations.
- The vanishing of even-frequency superconductivity highlights the distinct nature of odd-frequency superconductivity.
- A proposed experimental method allows for the unambiguous detection of the odd-frequency component.
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