Impurity-assisted Andreev reflection at a spin-active half-metal-superconductor interface

Abstract

The Andreev reflection amplitude at a clean interface between a half-metallic ferromagnet (H) and a superconductor (S) for which the half metal's magnetization has a gradient perpendicular to the interface is proportional to the excitation energy $\epsilon$ and vanishes at $\epsilon =0$ [Béri {\em et al.}, Phys.\ Rev.\ B {\bf 79}, 024517 (2009)]. Here we show that the presence of impurities at or in the immediate vicinity of the HS interface leads to a finite Andreev reflection amplitude at $\epsilon =0$. This impurity-assisted Andreev reflection dominates the low-bias conductance of a HS junction and the Josephson current of an SHS junction in the long-junction limit.

12 pages, 2 figures

References in corpus (5)

• A spin triplet supercurrent through the half-metallic ferromagnet CrO2
• Symmetries of Pairing Correlations in Superconductor-Ferromagnet Nanostructures
• Optimization of spin-triplet supercurrent in ferromagnetic Josephson junctions
• Quantum limit of the triplet proximity effect in half-metal - superconductor junctions
• Dephasing-enabled triplet Andreev conductance

Cited by in corpus (7)

• Spin-polarized supercurrents for spintronics: a review of current progress
• General Boundary Conditions for Quasiclassical Theory of Superconductivity in the Diffusive Limit: Application to Strongly Spin-polarized Systems
• Evidence for Half-Metallicity in n-type HgCr2Se4
• Theory of Andreev Bound States in S-F-S Junctions and S-F Proximity Devices
• Spin Transport in Half-Metallic Ferromagnet-Superconductor Junctions
• First-principles calculations of spin-triplet andreev reflection spectra at half-metallic ferromagnet/superconductor interface
• Theory of Andreev reflection spectroscopy with anisotropic spin-dependent scattering