Spin and charge control of single molecules for atomic scale quantum coherence
- Autores: Leonard Edens
- Directores de la Tesis: José Ignacio Pascual Chico (dir. tes.), Jose María Pitarque de la Torre (tut. 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
- Enlaces
- Tesis en acceso abierto en: ADDI
- Resumen
The quantum coherence of molecular spins, a platform for miniaturized quantum computation, is generally diminished when interfaced with conductive surfaces due to the Kondo effect, and magnetism can even be destroyed entirely by charge transfer. In this thesis, we explore several rationales for how the gas-phase electronic properties of isolated molecular spins can be protected from, or even enhanced by these interactions. For instance, magnetic chiral graphene nanoribbons, when spaced by a thin insulating MgO layer from a metallic substrate, support electronically decoupled but highly negative charge states are realized, whose ionicity and spin state are tuned purely by geometry. On the intermetallic ferromagnet GdAu2, instead a pristine half-filled molecular state manifests in the emergence of two characteristic symmetry-protected topological zero modes with local moments.
Employing a single nickelocene molecule as a spin probe, we map the substrate´s exchange field which favours alignment of radicals. To probe the quantum coherence of molecular spins, we augment a scanning tunnelling microscope with radiofrequency capability and perform electron spin resonance of an individual atom, obtaining state-of-the-art energy resolution. In this work, several molecular spin qubit candidates are realized by rational choice of both chemical structure and supporting surface.
