Structure and stability of Si(114)-(2x1)

We describe a recently discovered stable planar surface of silicon,-Si(114). This high-index surface, oriented 19.5 degrees away from (001) toward (111), undergoes a 2 x 1 reconstruction. We propose a complete model for the reconstructed surface based on scanning tunneling microscopy images and first-principles total-energy calculations. The structure and stability of Si(114)-(2 x 1) arises from a balance between surface dangling bond reduction and surface stress relief, and provides a key to understanding the morphology of a family of surfaces oriented between (001) and (114).