Sensing a magnetic rare-earth surface alloy by proximity effect with an open-shell nanographene
Abstract
Open-shell nanographenes have attracted significant attention due to their structurally tunable spin ground state. While most characterization has been conducted on weakly-interacting substrates such as noble metals, the influence of magnetic surfaces remains largely unexplored. In this study, we investigate how TbAu2, a rare-earth-element-based surface alloy, affects the magnetic properties of phenalenyl (or [2]triangulene (2T)), the smallest spin-1/2 nanographene. Scanning tunneling spectroscopy (STS) measurements reveal a striking contrast: while 2T on Au(111) exhibits a zero-bias Kondo resonance - a hallmark of a spin-1/2 impurity screened by the conduction electrons of the underlying metal - deposition on TbAu2 induces a symmetric splitting of this feature by approximately 20 mV. We attribute this splitting to a strong proximity-induced interaction with the ferromagnetic out-of-plane magnetization of TbAu2. Moreover, our combined experimental and first-principles analysis demonstrates that this interaction is spatially modulated, following the periodicity of the TbAu2 surface superstructure. These findings highlight that TbAu2 serves as a viable platform for stabilizing and probing the magnetic properties of spin-1/2 nanographenes, opening new avenues for the integration of {\pi}-magnetic materials with magnetic substrates.
Keywords
Cite
@article{arxiv.2505.10313,
title = {Sensing a magnetic rare-earth surface alloy by proximity effect with an open-shell nanographene},
author = {Nicolò Bassi and Jan Wilhelm and Nils Krane and Feifei Xiang and Patrícia Čmelová and Elia Turco and Pierluigi Gargiani and Carlo Pignedoli and Michal Juríček and Roman Fasel and Richard Koryt ár and Pascal Ruffieux and .},
journal= {arXiv preprint arXiv:2505.10313},
year = {2025}
}