Inelastic Decay of Electrons in the Shockley-type Metal-Organic Interface States

TL;DR

This paper provides a theoretical analysis of electron lifetimes in metal-organic interface states, explaining experimental observations and the effects of band structure and temperature on decay rates.

Contribution

It introduces a detailed theoretical framework for understanding inelastic decay of electrons at metal-organic interfaces, including the impact of band structure and temperature effects.

Findings

Lifetimes follow experimental trends

Brillouin zone folding has minor impact

Temperature increase leads to longer lifetimes

Abstract

We present a theoretical study of lifetimes of interface states (IS) on metal-organic interfaces PTCDA/Ag(111), NTCDA/Ag(111), PFP/Ag(111), and PTCDA/Ag(100), describing and explaining the recent experimental data. By means of unfolding the band structure of one of the interfaces under study onto the Ag(111) Brillouin zone we demonstrate, that the Brillouin zone folding upon organic monolayer deposition plays a minor role in the phase space for electron decay, and hence weakly affects the resulting lifetimes. The presence of the unoccupied molecular states below the IS gives a small contribution to the IS decay rate mostly determined by the change of the phase space of bulk states upon the energy shift of the IS. The calculated lifetimes follow the experimentally observed trends. In particular, we explain the trend of the unusual increase of the IS lifetimes with rising temperature.