Gutzwiller description of non-magnetic Mott insulators: Dimer lattice model

We introduce an extension of the Gutzwiller variational wave function able to deal with insulators that escape any mean-field-like description, as, for instance, nonmagnetic insulators. As an application, we study the Mott transition from a paramagnetic metal into a nonmagnetic Peierls, or valence-bond, Mott insulator. We analyze this model by means of our Gutzwiller wave function analytically in the limit of large coordination lattices, where we find that (1) the Mott transition is of first order; (2) the Peierls gap is large in the Mott insulator, although it is mainly contributed by the electron repulsion; and (3) singlet superconductivity arises around the transition.