# Quantum interference assisted spin filtering in graphene nanoflakes

## TL;DR

This paper explores how quantum interference and magnetism in graphene nanoflakes can enable nearly perfect spin filtering without external magnetic fields, advancing spintronic device potential.

## Contribution

It introduces a novel mechanism combining quantum interference and edge magnetism in graphene nanoflakes for spin-dependent transport control.

## Key findings

- Quantum interference patterns similar to benzene junctions in graphene nanoflakes.
- Nearly complete spin polarization of current achieved.
- Electrostatic control of spin polarization demonstrated.

## Abstract

We demonstrate that hexagonal graphene nanoflakes with zigzag edges display quantum interference (QI) patterns analogous to benzene molecular junctions. In contrast with graphene sheets, these nanoflakes also host magnetism. The cooperative effect of QI and magnetism enables spin-dependent quantum interference effects that result in a nearly complete spin polarization of the current, and holds a huge potential for spintronic applications. We understand the origin of QI in terms of symmetry arguments, which show the robustness and generality of the effect. This also allows us to devise a concrete protocol for the electrostatic control of the spin polarization of the current by breaking the sublattice symmetry of graphene, by deposition on hexagonal boron nitride, paving the way to switchable spin-filters. Such a system benefits of all the extraordinary conduction properties of graphene, and at the same time, it does not require any external magnetic field to select the spin polarization, as magnetism emerges spontaneously at the edges of the nanoflake.