Experimental studies of nitrogen adsorbed on a Cu(1 1 1) surface show that the surface layer undergoes a reconstruction to form a pseudo-(1 0 0) structure. We use ab initio techniques to demonstrate the theoretical stability of this reconstructed surface phase over a range of conditions. We systematically investigate the chemisorption of N on the Cu(1 1 1) surface, from 0.06 to 1 ML coverage. A peculiar atomic relaxation of N atoms for 0.75 ML is identified, which results in the formation of a (metastable) "N-trimer cluster" on the surface. We have also investigated surface nitride formation, as suggested from experiments. A surface nitride-like structure similar to the reported pseudo-(1 0 0) reconstruction is found to be highly energetically favored. Using concepts from "ab initio atomistic thermodynamics", we predict that this surface nitride exists for a narrow range of nitrogen chemical potential before the formation of bulk Cu3N.
Bibliographical noteFunding Information:
The authors gratefully acknowledge support from the Australian Research Council (ARC), the Australian Partnership for Advanced Computing (APAC) National Facility and the Australian Centre for Advanced Computing and Communications (ac3).
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Surfaces and Interfaces
- Surfaces, Coatings and Films
- Materials Chemistry