Quasicrystalline gold interface with a hypo-friction property

We have studied a non-symmetric and non-periodic grain boundary in gold. An atomic model is presented and the atomic positions are found to be in agre ement with the electron microscopy images. Using the diffraction pattern, w e show that the structure is quasicrystalline and related to the irrational number root 2. A complete hyperspace periodic description of the interface is given. We use this theoretical view to predict that in the case of an i nfinite interface of this type, two crystals should glide freely along the incommensurate x-direction whereas they should be blocked along the commens urate z-direction and be adhesive along the third y-direction perpendicular to the boundary. A numerical test confirms this property.