Dresden 2017 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 7: Electronic Structure of Surfaces: Magnetism and Spin Phenomena
O 7.1: Vortrag
Montag, 20. März 2017, 10:30–10:45, WIL C107
Magnetic properties of rare earth single atoms on metal substrates. — •Aparajita Singha1, Romana Baltic1, Fabio Donati1, Christian Wäckerlin1, Jan Dreiser1,2, Luca Persichetti3, Sebastian Stepanow3, Pietro Gambardella3, Stefano Rusponi1, and Harald Brune1 — 1Ecole Polytechnique Fédérale de Lausanne — 2Paul Scherrer Institute — 3ETH Zürich
Surface-supported rare earths (RE) single atoms have been recently shown to have unprecedented magnetic stability [Science 318, 352 (2016)]. However to further benefit from their intriguing properties requires an in-depth understanding of the interaction between RE atoms and the surface which defines the energy spectrum of their magnetic quantum levels. Here we show a systematic study of several REs (Dy, Ho, Er,and Tm) on different metal substrates (Pt(111), Cu(111), Ag(100), and Ag(111)). Using x-ray absorption spectroscopy and magnetic circular dichroism we reveal that only 4fn and 4fn−1 configurations are possible for these RE atoms where n corresponds to the free atom occupation. Moreover, we identify that the ionization potential of the 4f elements and the substrate density of states at the Fermi level are the two key factors governing the 4f occupation of the REs. All magnetization loops at 2.5 K show no hysteresis indicating that magnetic relaxation is faster than about 10 s. The comparison of our experimental spectra with multiplet calculations provides the identity and energy splitting of the magnetic quantum levels of these RE adatoms.