Atomic and electronic structure of an epitaxial N b 2 O 3 honeycomb monolayer on Au(111)

Shuqiu Wang (1) , Jacek Goniakowski (2, 3) , Claudine Noguera (2, 3) , Martin R. Castell (1)

1 Department of Materials
2 INSP - Institut des Nanosciences de Paris
3 INSP-E9 - Oxydes en basses dimensions

The experimental discovery and theoretical analysis of an epitaxial (2 × 2) honeycomb Nb 2 O 3 monolayer on a Au(111) surface is reported. The oxide monolayer is grown by Nb deposition and subsequent annealing in an oxidizing atmosphere. Scanning tunneling microscopy (STM) images show that the films form a well-ordered honeycomb lattice, and low energy electron diffraction patterns confirm that the films adopt a (2 × 2) periodicity with respect to the Au(111) substrate. Density functional theory (DFT) modeling shows that the Nb atoms are located in Au(111) threefold hollow sites and the O atoms are located in on-top positions. DFT also demonstrates the existence of a strong interfacial interaction characterized by a large electron transfer towards the Au substrate, an increase of the Nb oxidation state, and substantial film rumpling. High-resolution STM images, supported by simulations, are able to discriminate between Nb atoms adsorbed in fcc or hcp hollow sites on the Au(111) substrate.

Domaines: Matière Condensée [cond-mat]

Shuqiu Wang, Jacek Goniakowski, Claudine Noguera, Martin R. Castell. Atomic and electronic structure of an epitaxial N b 2 O 3 honeycomb monolayer on Au(111). Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2019, 100 (12), ⟨10.1103/PhysRevB.100.125408⟩. ⟨hal-02452262⟩