Generation and Manipulation of Spin Current in Graphene Nanodisks: Robustness against Randomness and Lattice Defects

TL;DR

This paper explores how trigonal zigzag graphene nanodisks can generate and control spin currents, demonstrating their robustness against randomness and defects, and proposing their use in spintronic devices.

Contribution

It introduces a method to generate and manipulate spin currents in graphene nanodisks, highlighting their robustness and potential for spintronic applications.

Findings

Nanodisks act as effective spin filters.

Spin currents can be manipulated with spin valves and switches.

Robustness of nanodisk spins against randomness and defects.

Abstract

Trigonal zigzag graphene nanodisk exhibits magnetism whose spin is proportional to the edge length of the nanodisk. Its spin can be designed from 1/2 to a huge value. The spins form a quasiferromagnet, which has intermediate properties between a single spin and a ferromagnet. In other words, the ferromagnet order has a relatively long life time, and yet the nanodisk spin can be rotated by external field or current. We consider a nanodisk connected with two leads. This system acts as a spin filter just as in a metal-ferromagnet-metal junction. In this way we can generate a spin current. Furthermore we can manipulate spin current by spin valve, spin switch and other spintronic devices made of graphene nanodisks. We also show that nanodisk spins are robust against the effect of randomness in site energy, transfer energy and lattice defects.