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O: Fachverband Oberflächenphysik
O 15: Spins on surfaces at the atomic scale I
O 15.11: Vortrag
Montag, 9. März 2026, 17:45–18:00, WILL/A317
Site-Specific magnetism of Ho atoms on MgO — •Andrés Pinar Solé1,2, Merve Ercelik1,2, Jungseok Chae1,2, Fabio Donati3, Dmitriy Borodin1,2, and Andreas Heinrich3 — 1Center for Quantum Nanoscience (QNS), Institute for Basic Science (IBS) — 2Ewha Womans University — 3Department of Physics, Ewha Womans University
Holmium (Ho) atoms on ultrathin MgO films are model systems for single-atom magnetism, where spin stability and relaxation strongly depend on the local crystal field and adsorption site. Isolated Ho atoms on oxygen sites of Ag(100)/MgO exhibit magnetic bistability but lack clear inelastic spin-excitation features; nevertheless, their magnetic states can be switched and read electrically through spin-polarized tunneling.
By extending to Ho dimers, additional spin-flip excitations become accessible, providing deeper insight into the electronic and magnetic states of Ho on MgO. The magnetic behavior of Ho dimers reflects the intra-atomic exchange coupling between the highly localized 4f moment and the outer valence-shell spins. Certain Ho dimers exhibit pronounced inelastic conductance steps, revealing strong magnetic interactions both between the atoms and with the surrounding MgO crystal field. Using STM-based atom manipulation, we precisely assemble Ho dimers on bridge and oxygen sites and probe their magnetic and electronic properties via Kelvin probe force microscopy (KPFM) and inelastic electron tunneling spectroscopy (IETS) in a combined STM/AFM UHV setup.
Keywords: single atom magnet; electronic structure; kpfm; afm; stm