Kondo effect and numerical renormalization group with realistic impurity models Symmetry-breaking effects and adsorbed polyradical molecules

• Autores: Aitor Calvo Fernández
• Directores de la Tesis: Asier Eiguren Goyenechea (dir. tes.), María Blanco Rey (codir. tes.)
• Lectura: En la Universidad del País Vasco - Euskal Herriko Unibertsitatea ( España ) en 2025
• Idioma: inglés
• 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
• Menciones:
  • Internacional
• Calificación: Sobresaliente Cum Laude
• Materias:
  • Física
• Enlaces
  • Tesis en acceso abierto en: ADDI
• Resumen

  • The Kondo effect is the screening of the local moment of a magnetic impurity by the conduction electrons in the host metal. Analyzing this phenomenon in real systems poses several challenges, both theoretical and computational, as it requires taking into account the degrees of freedom of the impurity and the hybridization with the host metal. To tackle this problem, we have developed a numerical renormalization group (NRG) procedure exploiting discrete point and double group symmetries, as well as particle conservation and spin space isotropy. We have implemented this procedure in the PointGroupNRG code, which is written in Julia and is openly distributed via GitHub. On top of that, we have rationalized the spatial distribution of the Kondo signal measured in several polyradical molecules adsorbed on metallic surfaces. To do so, we have used a combination of DFT and NRG methods, together with a generalized Schrieffer-Wolff transformation leading to the Kondo orbital basis set, which we have put forward as a means to understand the experimentally observed Kondo maps.