Zhenzhen Qin1 4 Guangzhao Qin2 Bin Shao3 Xu Zuo4

1, RWTH Aachen University, Aachen, , Germany
4, Nankai University, Tianjin, , China
2, RWTH Aachen University, Aachen, , Germany
3, Bremen University, Bremen, , Germany

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 presents a remarkable Rashba effect (the estimated strength is 1.89 eV Å) due to the strong SOC (~65.6 meV) and the asymmetric adsorption site at 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 on the ribbon width of first-order MAE as well as Rashba effect in Gd-ZGNRs are also examined. This work not only opens a new gate for designing 1D Rashba system but also provides insight into the unconventional MAE due to the intrinsic Rashba effect, which would be of great significance for searching Majorana fermions and promoting the potential applications in spintronics.