Wannier functions for one-dimensional s–p optical superlattices

The physics of one-dimensional optical superlattices with resonant s−p orbitals is reexamined in the language of appropriate Wannier functions. It is shown that details of the tight-binding model realized in different optical potentials crucially depend on the proper determination of Wannier functions. We discuss the properties of a superlattice model which quasiresonantly couples s and p orbitals and show its relation with different tight-binding models used in other works.