Spin-dependent THz oscillator based on hybrid graphene superlattices

TL;DR

This paper theoretically investigates spin-dependent Bloch oscillations in hybrid graphene superlattices, revealing spin-polarized THz currents resulting from spin-dependent Bloch amplitudes.

Contribution

It introduces a novel spin-dependent superlattice design in graphene that enables spin-polarized THz oscillations, combining ferromagnetic insulators with gapped graphene.

Findings

Bloch frequency is identical for both spins.

Bloch amplitude varies with spin, leading to polarization.

Results suggest potential for spintronic THz devices.

Abstract

We theoretically study the occurrence of Bloch oscillations in biased hybrid graphene systems with spin-dependent superlattices. The spin-dependent potential is realized by a set of ferromagnetic insulator strips deposited on top of a gapped graphene nanoribbon, which induce a proximity exchange splitting of the electronic states in the graphene monolayer. We numerically solve the Dirac equation and study Bloch oscillations in the lowest conduction band of the spin-dependent superlattice. While the Bloch frequency is the same for both spins, we find the Bloch amplitude to be spin dependent. This difference results in a spin-polarized ac electric current in the THz range.