Single-spin quantum sensing: A molecule-on-tip approach
Laurent Limot
Université de Strasbourg, CNRS, IPCMS, UMR 7504, F-67000 Strasbourg, France
Magnetometry plays a pivotal role in meeting the demands of ultra-dense storage technology and overcoming challenges associated with downscaled spin qubits. A promising approach for atomic-scale single-spin sensing involves utilizing a magnetic molecule as a spin sensor [1], although its practical realization remains in its early stages. To address this challenge and highlight the potential of this method, we combined a nickelocene molecule with scanning tunneling microscopy to perform versatile spin-sensitive imaging of magnetic surfaces.
We investigated model Co islands of varying thickness on Cu(111), exhibiting distinct magnetic properties [2]. Our method demonstrates robustness and reproducibility, providing atomic-scale sensitivity to spin polarization and magnetization orientation due to the direct exchange coupling between the nickelocene-terminated tip and the Co surfaces. This technique enables the acquisition of magnetic exchange maps, revealing unique signatures in the magnetic corrugation that align well with computed spin density maps. We will apply this method to examine the influence of hydrogen on magnetization [3], a topic of substantial interest in spintronics. These advancements significantly enhance our ability to probe and visualize magnetism at the atomic level.
[1] B. Verlhac, N. Bachellier, L. Garnier, M. Ormaza, P. Abufager, R. Robles, M.-L. Bocquet, M. Ternes, N. Lorente, L. Limot, Science 366, 623 (2019)
[2] A. Fétida, O. Bengone, M. Romeo, F. Scheurer, R. Robles, N. Lorente, L. Limot, ACS Nano 18, 13829 (2024)
[3] A. Fétida, O. Bengone, C. Goyhenex, F. Scheurer, R. Robles, N. Lorente, L. Limot, Sci. Adv. 11, eads1456 (2025)