  Grain boundaries with [111] tilt axes are common in polycrystalline face
centered cubic metals. For copper (111) films, emergent grain boundaries close
to surface have tilt axes that are shifted away from [111] that are lower in
energy than the corresponding truncated bulk boundaries. Geometrical analysis
and atomic calculations were used to study the driving force for this same
relaxation phenomenon in representative fcc elemental metals. We show that the
reduction in boundary energy scales with the elimination of energetically
costly boundary core facets. We find that for a wide range of misorientation
angles low energy core-shifted boundaries are also favored in Al, Ni, Au and Pt
and discuss the significance for electromigration and other metal properties.
