Faceting and stress of missing-row reconstructed transition-metal (110) surfaces

We present ab initio total energy and stress calculations for the unreconst ructed and (2x1)-missing-row reconstructed Ir (110) and Rh (110) surfaces. We then use those results to set up a model rationalizing the (2x1) reconst ruction as a faceting transition to a long-wavelength-corrugated (111)-like surface. Next, we discuss the qualitative extension of such model to a gen eral nx1 reconstruction, using ab initio results, elasticity theory, and cl assical dynamics simulations for Al (110). Remarkably, despite the severe i nherent limitations of the model, the 3x1 structure is found to be the most stable for Ir. Finally, we use the stress density to analyze the stress in crease upon reconstruction, and find it to be due to a changed balance of t ensile and compressive contributions in the near-surface region, which clos ely matches previous interpretations of the reconstruction mechanism. We co nclude that, as for the (100) surface, the reconstruction basically origina tes from the strong relativistic contraction effects on the electronic stru cture of end-of-series 5d metals. [S0163-1829(99)04643-3].