Magnetic properties of co on different environments

• Autores: Iker Gallardo Arrieta
• Directores de la Tesis: Fernando Delgado Acosta (dir. tes.), Andres Arnau Pino (dir. tes.)
• Lectura: En la Universidad del País Vasco - Euskal Herriko Unibertsitatea ( España ) en 2019
• Idioma: inglés
• Tribunal Calificador de la Tesis: Jorge Iribas Cerda (presid.), María Blanco Rey (secret.), Stefano Rusponi (voc.)
• Programa de doctorado: Programa de Doctorado en Física de Nanoestructuras y Materiales Avanzados/Physics of Nanostructures and Advanced Materials por la Universidad del País Vasco/Euskal Herriko Unibertsitatea
• Materias:
  • Física
    • Electromagnetismo
      • Magnetismo
    • Física del estado sólido
      • Propiedades magnéticas
      • Superficies
• Enlaces
  • Tesis en acceso abierto en: ADDI
• Resumen

  • We combine density functional theory (DFT) calculations and a multiorbital many-body Hamiltonian approach to shed light on magnetic properties of Co adsorbed on h-BN depending on the adsorption site. These methods reveal an out-of-plane easy axis anisotropy for atop N site and hard axis for hollow site, with an electronic configuration close to 3d8, corresponding to a spin S = 1. Then, we compare our results with x-ray absorption spectroscopy (XAS), x-ray magnetic circular dichroism (XMCD) and x-ray magnetic linear dichroism (XMLD) measurements on Co/h-BN/Ir(111) and Co/h-BN/Ru(0001). XAS and XMCD data show large (14 meV) out-of-plane anisotropy for Co/h-BN/Ru(0001) and almost isotropic for Co/h-BN/Ir(111), while both have an electronic structure compatible with spin S = 1. We use this information to determine the atop N adsorption of Co on h-BN/Ru(0001) and hollow for the Co on h-BN/Ir(111). XMLD data together with DFT and multiorbital Hubbard model results suggest that the different adsorption sites induce dissimilar anisotropy of Co. Finally, we explain from DFT calculations the counterintuitive downward shift of the Au(111) surface state measured by angle resolved photo-emission spectroscopy (ARPES) when two homothetic Co-coordinated metal-organic nanoporous networks (MONN) are self-assembled. We associate this effect to the weak Co-substrate hybridization and show that it appears with different adatoms and substrates.