Spin-polarized currents and noise in normal-metal/superconductor junctions with Yu-Shiba-Rusinov impurities
Journal article, 2016

Conventional superconductors disordered by magnetic impurities demonstrate physical properties that are drastically different from their pristine counterparts. In our previous work [D. Persson et al., Phys. Rev. B 92, 245430 (2015)], we explored the spectral and thermodynamic properties of such systems for two extreme cases: completely random and ferromagnetically aligned impurity magnetic moments. Here we consider the transport properties of these systems and show that they have a potential to be used in superconducting spintronic devices. Each magnetic impurity contributes a Yu-Shiba-Rusinov (YSR) bound state to the spectrum, residing at subgap energies. Provided the YSR states form metallic bands, we demonstrate that the tunneling current carried by these states can be highly spin polarized when the impurities are ferromagnetically ordered. The spin polarization can be switched by tuning the bias voltage. Moreover, even when the impurity spins are completely uncorrelated, one can still achieve almost 100% spin polarization of the current, if the tunnel interface is spin active. We compute electric current and noise, varying parameters of the interface between tunneling and fully transparent regimes, and analyze the relative role of single-particle and Andreev reflection processes.

Author

Daniel Persson

Chalmers, Microtechnology and Nanoscience (MC2), Applied Quantum Physics

Oleksii Shevtsov

Chalmers, Microtechnology and Nanoscience (MC2), Applied Quantum Physics

Tomas Löfwander

Chalmers, Microtechnology and Nanoscience (MC2), Applied Quantum Physics

Mikael Fogelström

Chalmers, Microtechnology and Nanoscience (MC2), Applied Quantum Physics

Physical Review B: covering condensed matter and materials physics

2469-9969 (eISSN)

Vol. 94 155424-

Driving Forces

Sustainable development

Areas of Advance

Nanoscience and Nanotechnology (2010-2017)

Roots

Basic sciences

Subject Categories

Condensed Matter Physics

DOI

10.1103/PhysRevB.94.155424

More information

Created

10/7/2017