MN4 Embedded Graphene Layers: Tunable Decay Rate of RKKY Interaction

TL;DR

This study investigates MN4 embedded graphene layers with transition metals, revealing tunable RKKY interactions with prolonged decay rates, and contrasting behaviors influenced by the CuN4 moiety, advancing 2D magnetic spintronic materials.

Contribution

It demonstrates that MN4-G layers with M=Fe, Mn, Co exhibit tunable RKKY interactions with unusual decay rates, and shows the unique behavior of CuN4-G as decoupled spin chains.

Findings

RKKY interactions are tunable in MN4-G layers.

Decay rate of RKKY interaction varies between r^-0.5 and r^-2.

CuN4-G behaves as decoupled 1D spin chains.

Abstract

One of the most important tasks in the development of high-performance spintronic devices is the preparation of two dimensional (2D) magnetic layers with long-range exchange interactions. MN4 embedded graphene (MN4-G) layers, with M being transition metal elements, are experimentally accessible 2D layers, which exhibit interesting magnetic properties. In this paper, by employing the spin-polarized density functional theory (SP-DFT), we study MN4-G layers with a special focus on the behavior of the indirect M-M exchange interactions, and demonstrate that the MN4-Gs with M = Fe, Mn and Co, are 2D anisotropic magnetic layers with Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction. By examining the electronic configurations of the M atoms for various M-M spacers, we demonstrate that the RKKY interaction in such layers are tunable and exhibiting an unusual prolonged decay (r to the power of minus n, n between 0.5 and 2). In addition, we investigate the influence of the CuN4 moiety in the graphene host, and show that, in contrary to the other MN4-Gs, the 2D CuN4-G layer behaves as decoupled one-dimensional spin chains, regardless of the spacer lengths.