Regensburg 2013 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 62: Focussed Session: Frontiers of Electronic Structure Theory VI (jointly with HL and TT)
O 62.9: Vortrag
Donnerstag, 14. März 2013, 12:45–13:00, H36
Thermionic emission from metal surfaces: A first principles study — •Johannes Voss1, Sharon Chou1, Aleksandra Vojvodic1,2, Igor Bargatin3, Roger Thomas Howe1, and Frank Abild-Pedersen2 — 1Stanford University, USA — 2SLAC National Accelerator Laboratory, USA — 3University of Pennsylvania, USA
The ability to lower the temperatures required for sufficient electronic emission from hot cathodes would lead to more efficient thermionic energy converters and electron guns. Thermionic emission of electrons from metal surfaces is governed by the work function and tunneling probabilities. While the former can be extracted easily from ab initio band structure calculations, for the latter, scattering properties of the surface need to be taken into account.
Here, we present density functional theory calculations of thermionic emission currents based on a non-equilibrium Green’s function approach. We compare these results to experiments both for clean and coated metal surfaces. Based on an analysis of interactions in the coating layers, we suggest design pathways for new materials with higher emission current densities.