Surface polarization and edge charges

The term ``surface polarization'' is introduced to describe the in-plane polarization existing at the surface of an insulating crystal when the in-plane surface inversion symmetry is broken. Here, the surface polarization is formulated in terms of a Berry phase, with the hybrid Wannier representation providing a natural basis for study of this effect. Tight-binding models are used to demonstrate how the surface polarization reveals itself via the accumulation of charges at the corners and edges for a two dimensional rectangular lattice and for GaAs respectively.