Unconventional superconducting states induced in a ferromagnet by a d-wave superconductor

TL;DR

This paper presents a quasi-classical theory explaining how a d-wave superconductor induces unconventional superconducting states in a ferromagnet, showing oscillations in the density of states influenced by the superconductor's orientation.

Contribution

It introduces a theoretical framework for understanding the anisotropic and oscillatory proximity effect in ferromagnet/d-wave superconductor heterostructures.

Findings

Density of states oscillates with ferromagnet thickness

Oscillation characteristics depend on superconductor orientation

Spatial oscillations and anisotropy of induced correlations are demonstrated

Abstract

We develop a quasi-classical theory for the superconducting proximity effect in a ballistic ferromagnetic layer in contact with a d-wave superconductor. In agreement with recent experiments we find that the density of states oscillate around the normal state value with varying the thickness of the ferromagnetic layer. We show that the phase, the amplitude, and the period of these oscillations depend on the orientation of the superconductor. This effect reveals spatial oscillations and anisotropy of the induced superconducting correlations in the ferromagnet.