Electronic Whispering Gallery Modes and Enhanced Magnetic Interactions in Graphene
Abstract: Engineering electromagnetic density of states through optical cavities has led to a range of physical phenomena such as Purcell enhancement of spontaneous emission, coherent control of emitters, Dicke super-radiance in cavity QED systems. Motivated by cavity QED systems we have theoretically investigated the possibility of creating electronic cavities and using the cavity modes to create enhanced, long ranged Ruderman-Kittel-Kasuya-Yosida(RKKY) type magnetic interactions in graphene.
We study the RKKY interaction between two magnetic impurities in pristine graphene in the presence of circular electric potentials. In bulk graphene structures RKKY interaction shows a power law decay with distance in doped and undoped cases. However under a circular electrical confinement quasi-bound states are shown to mediate long range RKKY interactions between magnetic moments in the vicinity of the circular potential. It is shown that depth of the potential well and amount of doping can be tuned to enhance the RKKY interaction. The predicted effect can enable electrical control of RKKY interactions in graphene and similar two dimensional materials.