Clocked single-spin source based on a spin-split superconductor

TL;DR

This paper introduces a precise, clocked single-spin source device utilizing a superconducting island with ferromagnetic insulator layers, enabling controlled spin transfer for ac-spintronic applications with MHz operation.

Contribution

It presents a novel device design combining superconductors and ferromagnetic insulators to achieve accurate, clocked single-spin transfer with suppressed Andreev reflection.

Findings

Device can produce clocked spin currents in the MHz range

Ferromagnetic insulator layer enhances spin polarization and accuracy

Realistic material combinations and experimental conditions identified

Abstract

We propose an accurate clocked single-spin source for ac-spintronic applications. Our device consists of a superconducting island covered by a ferromagnetic insulator layer through which it is coupled to superconducting leads. Single-particle transfer relies on the energy gaps and the island's charging energy, and is enabled by a bias and a time-periodic gate voltage. Accurate spin transfer is achieved by the ferromagnetic insulator layer which polarizes the island, provides spin-selective tunneling barriers and improves the precision by suppressing Andreev reflection. We analyze realistic material combinations and experimental requirements which allow for a clocked spin current in the MHz regime.