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MA: Fachverband Magnetismus

MA 19: Surface Magnetism

MA 19.11: Vortrag

Dienstag, 19. März 2024, 12:15–12:30, EB 407

Magnetic state of rare earth atoms on NaCl films — •María Blanco-Rey^1,2,3, Fernando Delgado⁴, Andrés Arnau^1,2,3, Marina Pivetta⁵, Stefano Rusponi⁵, and Harald Brune⁵ — ¹Universidad del País Vasco UPV/EHU, Spain — ²Donostia International Physics Center DIPC, Spain — ³Centro de Física de Materiales MPC-CSIC-UPV/EHU, Spain — ⁴Universidad de La Laguna, Spain — ⁵École Polytechnique Fédérale de Lausanne EPFL, Switzerland

A combination of STM and XAS experiments shows that rare earth atoms on NaCl/Ag have 4fⁿ and 4fⁿ⁻¹ electronic configurations depending on the adsorption site. The NaCl film thickness determines the preferred adsorption site, which in turn defines the occupation of the 5d shell. In this contribution we show that DFT calculations for Gd and Eu ad-atoms can mimic the energetics and electronic occupation of the 6s5d shells, predicting a 4fⁿ⁻¹ configuration for the rare earth as a Na substitutional, an adsorption geometry that is favorable for 2ML of NaCl only. For thicker films, defect formation is hindered and only 4fⁿ species are allowed. As the rare earth atom becomes decoupled from the Ag substrate, there is a preference for adsorption sites with reduced coordination.

Keywords: Rare earth; DFT; Valency; Defects; XMCD