Emerging 2D-ferromagnetism and strong spin-orbit coupling at the surface of valence-fluctuating EuIr2Si2

Research output: Contribution to journalArticle


The development of materials that are non-magnetic in the bulk but exhibit two-dimensional (2D) magnetism at the surface is at the core of spintronics applications. Here, we present the valence-fluctuating material EuIr2Si2, where in contrast to its non-magnetic bulk, the Si-terminated surface reveals controllable 2D ferromagnetism. Close to the surface the Eu ions prefer a magnetic divalent configuration and their large 4f moments order below 48 K. The emerging exchange interaction modifies the spin polarization of the 2D surface electrons originally induced by the strong Rashba effect. The temperature-dependent mixed valence of the bulk allows to tune the energy and momentum size of the projected band gaps to which the 2D electrons are confined. This gives an additional degree of freedom to handle spin-polarized electrons at the surface. Our findings disclose valence-fluctuating rare-earth based materials as a very promising basis for the development of systems with controllable 2D magnetic properties which is of interest both for fundamental science and applications.


  • Susanne Schulz
  • Ilya A. Nechaev
  • Monika Güttler
  • Georg Poelchen
  • Alexander Generalov
  • Steffen Danzenbächer
  • Alla Chikina
  • Silvia Seiro
  • Kristin Kliemt
  • Alexandra Yu Vyazovskaya
  • Timur K. Kim
  • Pavel Dudin
  • Evgueni V. Chulkov
  • Clemens Laubschat
  • Eugene E. Krasovskii
  • Christoph Geibel
  • Cornelius Krellner
  • Kurt Kummer
  • Denis V. Vyalikh
External organisations
  • Dresden University of Technology
  • CSIC Centro de Física de Materiales (UPV/EHU)
  • Donostia International Physics Center (DIPC)
  • Paul Scherrer Institute
  • Leibniz Institute for Solid State and Materials Research
  • Goethe University
  • Tomsk State University
  • Saint Petersburg State University
  • Diamond Light Source
  • University of the Basque Country
  • Basque Foundation for Science
  • Max Planck Institute for Chemical Physics of Solids
  • European Synchrotron Radiation Facility
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Condensed Matter Physics
Original languageEnglish
Article number26
Journalnpj Quantum Materials
Issue number1
Publication statusPublished - 2019
Publication categoryResearch