Theory of ultrafast electron transfer from localized quantum states at surfaces

Résumé

The ability of materials to transfer electrons is a basic property controlling the functionality and performance of devices at the nanoscale. Of particular importance is the tranfor of electros at surfaces as a fundamental process in catalytic and photocatalytic applications. This work aims along these lines at a theoretical description of resonant charge injection at surfaces using a combination of density functional theory and Green's functions. A close comparison with available data from core-hole-clock experiments is maintained throughout the work and confirms the validity and predictive power of our first-principles approach. This is demonstrated on the basis of three prototypical systems where we study fundamental aspects of charge transfer, providing additional, often complementary information to the interpretation of the experiments. First, we present a detailed study of the effects of structural fluctuations on elastic charge transfer for isonicotinic acid adsorbed on rutile (110) in relation to photovoltaic applications. Second we explore spin-dependent charge injection from core-excited argon resonances on Co(0001) and Fe(110), with possible implications for spintronics. Third, we examine the directionality of charge transfer from sulfur related resonances at surfaces of layered 1T-TaS2 in the commensurate charge density wave phase.