Magnetic adatoms coupled to an $s$-wave superconductor give rise to local bound states, so-called Yu-Shiba-Rusinov states. Focusing on the ultimate goal of tailoring chains of such adatoms into a topologically superconducting phase, we investigate basic building blocks—single Fe and Mn adatoms and Mn dimers on clean superconducting Ta(110)—using scanning tunneling microscopy and spectroscopy. We perform a systematic study of the hybridizations and splittings in dimers, and their dependence on the crystallographic directions and interatomic spacings, in order to identify potentially interesting chain geometries for this sample type. Subsequently, we study the spin structure as well as the length dependent Shiba band structure in Mn chains of those geometries using spin-resolved scanning tunneling spectroscopy. All results are compared to the according properties of structurally identical dimers and chains on the previously studied Nb(110), which has almost identical surface structure and electronic properties, but an about three times smaller spin-orbit interaction.

• Received 13 May 2022
• Revised 20 December 2022
• Accepted 20 January 2023

DOI:https://doi.org/10.1103/PhysRevB.107.024426