Prediction of Stable Surfaces of Metal Oxides through the Unsaturated Coordination Index

This study proposesthe unsaturated coordination index, & sigma;,as a potential descriptor of the stability of metal-oxide surfacescleaved from bulk. The value of & sigma;, the number of missing bondsper unit area, can be obtained very quickly using only crystallographicdata, namely, the bulk geometry. The surface energies of various binaryoxides, with and without atom relaxation, were calculated. Their correlationswith & sigma; had good coefficients of determination (R (2)) values, particularly in high-symmetry crystals. Theproposed descriptor is very useful for an initial evaluation of stablemetal-oxide surfaces without conducting any surface model calculations.

Automated summary

This study proposes the unsaturated coordination index, σ, as a potential descriptor for the stability of metal-oxide surfaces. The value of σ, representing the number of missing bonds per unit area, can be quickly obtained using only crystallographic data, specifically the bulk geometry. The calculated surface energies of various binary oxides show good correlations with σ, particularly in high-symmetry crystals. This descriptor is useful for an initial evaluation of stable metal-oxide surfaces without the need for surface model calculations.