Unconventional magnetic anisotropy in one-dimentional Rashba system realized by adsorbing Gd atom on zigzag graphene nanoribbons

TL;DR

This study proposes a new method to realize one-dimensional Rashba systems by adsorbing Gd atoms on zigzag graphene nanoribbons, revealing unconventional magnetic anisotropy and strong spin-orbit coupling effects relevant for spintronics.

Contribution

It introduces a novel approach to achieve 1D Rashba effects through Gd adsorption on graphene nanoribbons and uncovers unconventional magnetic anisotropy contributions.

Findings

Perpendicular magnetic anisotropy energy observed.

Strong Rashba effect with estimated strength of 1.89 eV Å.

First-order MAE linked to intrinsic Rashba effect, beyond traditional second-order MAE.

Abstract

The Rashba effect, a spin splitting in electronic band structure, attracts much attention for the potential applications in spintronics with no requirement of external magnetic field. Realizing one-dimensional (1D) Rashba system is a big challenge due to the difficulties of growing high-quality heavy-metal nanowires or introducing strong spin-orbit coupling (SOC) and broken inversion symmetry in flexible materials. Here, based on first-principles calculations, we propose a pathway to realize the Rashba spin-split by adsorbing Gd atom on zigzag graphene nanoribbons (Gd-ZGNR) and further investigate the magnetic anisotropy energy (MAE). Perpendicular MAE and unconventional MAE contributions in k-space are found in the self-assembled Gd-ZGNR system, which present a remarkable Rashba effect (the estimated strength is 1.89 eV {\AA}) attributed to strong SOC (~65.6 meV) and the asymmetric adsorption site at the nanoribbons edge. Moreover, first-order MAE is connected to the intrinsic Rashba effect beyond the traditional second-order MAE, which is confirmed based on the analysis of electronic structures perturbed with SOC in comparison with metastable Gd-ZGNR at central symmetric adsorption site. The dependence of first-order MAE as well as Rashba effect of Gd-ZGNRs on the ribbon width are also examined. This work offers new perspective to achieve 1D Rashba system and provides fundamental understanding on the magnetic anisotropy, which would be of great significance for searching Majorana fermions and promoting the potential applications in spintronics.