Perfect spin filter by periodic drive of a ferromagnetic quantum barrier

TL;DR

This paper demonstrates that a periodically driven ferromagnetic quantum barrier can act as a highly-tunable spin filter, with sharp resonances enabling perfect transmission or reflection for spintronic devices.

Contribution

It introduces a model combining Floquet formalism and interactions to show how periodic driving controls spin-dependent tunneling in quantum barriers.

Findings

Periodic potential induces sharp transmission and reflection resonances.

Resonances are tunable via frequency, driving strength, and magnetic field.

Device can function as a highly-tunable spin valve for spintronics.

Abstract

We consider the problem of particle tunneling through a periodically driven ferromagnetic quantum barrier connected to two leads. The barrier is modeled by an impurity site representing a ferromagnetic layer or quantum dot in a tight-binding Hamiltonian with a local magnetic field and an AC-driven potential, which is solved using the Floquet formalism. The repulsive interactions in the quantum barrier are also taken into account. Our results show that the time-periodic potential causes sharp resonances of perfect transmission and reflection, which can be tuned by the frequency, the driving strength, and the magnetic field. We demonstrate that a device based on this configuration could act as a highly-tunable spin valve for spintronic applications.