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MA: Fachverband Magnetismus

MA 19: Surface Magnetism

MA 19.7: Talk

Tuesday, March 19, 2024, 11:15–11:30, EB 407

The quest for Single Atom Magnets: the case of Dy adatoms on SrTiO₃ surfaces — Valerio Bellini¹, Stefano Rusponi², Marina Pivetta², Pietro Gambardella³, Harald Brune², Carlo Carbone⁴, and •Alessandro Barla⁴ — ¹S3-Istituto di Nanoscienze-CNR, Modena, Italy — ²Institute of Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland — ³Department of Materials, ETH Zurich, Zurich, Switzerland — ⁴Istituto di Struttura della Materia-CNR, Trieste, Italy

We present a case study of rare-earth Dy and Ho single atoms deposited on the surface of SrTiO₃ using a combined theoretical and experimental approach [1]. X-ray magnetic circular dichroism reveals slow relaxation of the Dy magnetization on a time scale of about 800 s at 2.5 K, unusually associated with an easy-plane magnetic anisotropy. With the help of first-principles calculations and atomic multiplet simulations we rationalise this observation in terms of the magnetic properties of the Dy atoms as a function of the occupation sites on the coexisting TiO₂ and SrO-terminated surface. Interestingly, the adsorption of Dy on the insulating SrTiO₃ crystal leads to the formation of a spin-polarized two-dimensional electron gas, that couples antiferromagnetically to the Dy spin moments.

[1] V. Bellini, S. Rusponi, J. Kolorenč, S. K. Mahatha, M.A. Valbuena, L. Persichetti, M. Pivetta, B. V. Sorokin, D. Merk, S. Reynaud, D. Sblendorio, S. Stepanow, C. Nistor, P. Gargiani, D. Betto, A. Mugarza, P. Gambardella, H. Brune, C. Carbone, and A. Barla. ACS Nano 16, 11182 (2022).

Keywords: Single atom magnets; Density-Functional Theory; X-ray magnetic circular dichroism