Berlin 2015 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 88: Electronic Structure: Surface Magnetism and Spin Phenomena
O 88.1: Vortrag
Donnerstag, 19. März 2015, 15:00–15:15, MA 042
Tuning the zero field splitting of single porphyrin molecules on Pb(111) — •Benjamin W. Heinrich1, Lukas Braun1, José I. Pascual2, and Katharina J. Franke1 — 1Institut für Experimentalphysik, Freie Universität Berlin, Germany — 2CIC nanoGUNE, San Sebastián, and Ikerbasque, Basque Foundation for Science, Bilbao, Spain.
Magnetism in reduced dimensions is governed by the local chemical structure and the interaction with the surrounding on an atomic scale. Here we employ the tip of a low-temperature scanning tunneling microscope to modify reversibly the ligand field of a transition metal atom. Two metal-organic complexes – one high-spin and one intermediate-spin complex – adsorbed on the type I superconductor Pb(111) are studied at 1.2 K. Inelastic electron tunneling spectra reveal changes of the zero field splitting of the spin eigenstates in the order of 10% for both molecules due to the changed potential landscape experienced by the paramagnetic atom.
We explain our results by variations of the ligand field, which modify the d-level splitting and thereby the zero field splitting. These experiments highlight the importance of subtle differences in the geometry and surrounding potential, which influence the strength of magnetocrystalline anisotropy in transition metal complexes.