MOTT TRANSITION IN AN EXACTLY SOLVABLE K.S.S.H. MODEL

B. Sriram Shastry

Élliott H. Lieb, Fa Yueh Wu

Wayne Zheng, Yuan-Ming Lu

Arianna Montorsi, Mario Rasetti

The solution of the K.S.S.H.-like model shown to be exactly solvable in any number of dimensions, for a particular choice of the coupling constant describing the hopping process amplitude, both for finite size and in the thermodynamic limit, is discussed in detail. The analysis of the zero-temperature phase space in d = 2 shows that the model exhibits a transition in the number of doubly occupied sites order parameter, which at half-filling coincides with the Mott transition found for the Hubbard model in the Gutzwiller approximation.

R. Shankar

A solvable model of d = 1 spinless fermions at half-filling which exhibits a Mott transition is studied in detail. Many response functions are computed: at zero and nonzero temperatures, in the insulating and metallic sites, at the transition, and at q ≃ 0, 2k F . Some quantities are computed exactly, others only upto a scale factor. Some results are old, but mentioned here for completeness. Some are rederived using new tools such as conformal invariance. The rest are new. Next, the effect of randomness on the Mott state is explored. It is found, on the basis of Imry-Ma type arguments that no matter how large the gap is, the Mott insulator turns into an Anderson insulator immediately.

M. A. Contínentino, Mauricio D. Coutinho-Filho