Superlattices effective mass

The mass ratio above 100, required for the observation of the crystalline order, can be achieved in an optical lattice with a small filling factor for heavy atoms. Their effective mass in the lattice, Af, can be made very large, and the discussed solid phase should appear as a superlattice. There is no interplay between the superlattice order and the shape of the underlying optical lattice, in contrast to the recently studied solid and supersolid phases in a triangular lattice with the filling factor of order one [78-80]. The superlattice discussed in our review remains compressible and supports two branches of phonons. 

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