title: Restoring the Co magnetic moments at interfacial Co-porphyrin arrays by site-selective uptake of iron.
abstract: Magnetochemistry recently emerged as a promising approach to control addressable spin arrays on surfaces. Here we report on the binding, spatial ordering, and magnetic properties of Fe on a highly regular Co-tetraphenylporphyrin (Co-TPP) template and highlight how the Fe controls the magnetism of the Co centers. As evidenced by scanning tunneling microscopy (STM) single Fe atoms attach to the saddle-shape conformers site-selectively in a unique coordination environment offered through a heptamer defined by the Co-N-C-C-C-N cyclic subunit. While the magnetic moment of Co is quenched for bare Co-TPP/Ag(111), the Fe presence revives it. Our X-ray magnetic circular dichroism (XMCD) experiments, complemented by density functional theory (DFT) calculations, evidence a ferromagnetic coupling between the Fe and the Co center concomitant with a complex charge redistribution involving the porphyrin ligand. Thus, we demonstrate an unusual metalloporphyrin coordination geometry that opens pathways to spatially order and engineer magnetic moments in surface-based nanostructures.
authors: †Physik-Department E20, Technische Universität München, D-85748 Garching, Germany.
authors: Saranyan
authors: S
authors: Vijayaraghavan
authors: †Physik-Department E20, Technische Universität München, D-85748 Garching, Germany.
authors: Willi
authors: W
authors: Auwärter
authors: †Physik-Department E20, Technische Universität München, D-85748 Garching, Germany.
authors: David
authors: D
authors: Ecija
authors: †Physik-Department E20, Technische Universität München, D-85748 Garching, Germany.
authors: Knud
authors: K
authors: Seufert
authors: ‡Institute of Condensed Matter Physics (ICMP), Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
authors: Stefano
authors: S
authors: Rusponi
authors: §Université de Lyon, CNRS, Ecole Normale Supérieure de Lyon, Laboratoire de Chimie, F-69364 Cedex 07 Lyon, France.
authors: Torsten
authors: T
authors: Houwaart
authors: §Université de Lyon, CNRS, Ecole Normale Supérieure de Lyon, Laboratoire de Chimie, F-69364 Cedex 07 Lyon, France.
authors: Philippe
authors: P
authors: Sautet
authors: §Université de Lyon, CNRS, Ecole Normale Supérieure de Lyon, Laboratoire de Chimie, F-69364 Cedex 07 Lyon, France.
authors: Marie-Laure
authors: ML
authors: Bocquet
authors: ⊥European Synchrotron Radiation Facility (ESRF), B.P. 220, Grenoble Cedex F-38043, France.
authors: Pardeep
authors: P
authors: Thakur
authors: ∥Department of Materials, ETH Zürich, Hönggerbergring 64, CH-8093 Zürich, Switzerland.
authors: Sebastian
authors: S
authors: Stepanow
authors: ‡Institute of Condensed Matter Physics (ICMP), Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.|#Max Planck Institut für Festkörperforschung, D-70569 Stuttgart, Germany.
authors: Uta
authors: U
authors: Schlickum
authors: ‡Institute of Condensed Matter Physics (ICMP), Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.|#Max Planck Institut für Festkörperforschung, D-70569 Stuttgart, Germany.
authors: Markus
authors: M
authors: Etzkorn
authors: ‡Institute of Condensed Matter Physics (ICMP), Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
authors: Harald
authors: H
authors: Brune
authors: †Physik-Department E20, Technische Universität München, D-85748 Garching, Germany.
authors: Johannes V
authors: JV
authors: Barth
keywords: X-ray magnetic circular dichroism (XMCD); density functional theory (DFT); magnetic moment; magnetochemistry; metalloporphyrin; scanning tunneling microscopy (STM); template