Focusing RKKY interaction by graphene P-N junction

TL;DR

This paper demonstrates that electron focusing in graphene P-N junctions can be used to control and enhance the RKKY interaction between local spins, enabling new spintronic applications.

Contribution

It introduces a novel method to manipulate RKKY interactions using electron optics phenomena in graphene P-N junctions, differing from traditional uniform system approaches.

Findings

Focusing electron waves refocuses RKKY interaction between spins.

The method produces non-oscillatory, symmetry-protected RKKY interactions.

Enhanced long-range spin-spin coupling in graphene achieved.

Abstract

The carrier-mediated RKKY interaction between local spins plays an important role for the application of magnetically doped graphene in spintronics and quantum computation. Previous studies largely concentrate on the influence of electronic states of uniform systems on the RKKY interaction. Here we reveal a very different way to manipulate the RKKY interaction by showing that the anomalous focusing - a well-known electron optics phenomenon in graphene P-N junctions - can be utilized to refocus the massless Dirac electrons emanating from one local spin to the other local spin. This gives rise to rich spatial interference patterns and symmetry-protected non-oscillatory RKKY interaction with a strongly enhanced magnitude. It may provide a new way to engineer the long-range spin-spin interaction in graphene.