The influence of spin-dependent phases of tunneling electrons on the conductance of a point ferromagnet/isolator/d-wave superconductor contact

TL;DR

This paper investigates how spin-dependent phase shifts affect electron tunneling and conductance in ferromagnet/insulator/d-wave superconductor contacts, revealing orientation-dependent conductance features and the formation of Andreev bound states.

Contribution

It introduces a detailed analysis of phase shifts' effects on Andreev reflection and conductance in FIS contacts, highlighting orientation-dependent phenomena and bound state formation.

Findings

Zero-bias conductance peak disappears with increasing ferromagnet polarization in (110) orientation.

Conductance peak persists in (100) orientation despite polarization.

Surface Andreev bound states form due to interference of quasiparticles.

Abstract

The influence of phase shifts of electron waves passing through and reflected by the potential barrier on the Andreev reflection in a ferromagnet/isolator/d-wave superconductor (FIS) contact is studied. It is found that in a superconductor the surface spin-dependent Andreev bound states inside the superconducting gap are formed as a result of the interference of electron-like and hole-like quasiparticles due to repeated Andreev reflections. The peak in the conductance of the FIS contact at the zero potential for the (110)-oriented superconductor disappears rapidly as the polarization of a ferromagnet increases, whereas for the (100)-oriented superconductor it appears. The physical reason for this behavior of conductance is discussed.