  We discuss the solution of the Mott transition problem in a fully frustrated
lattice with a semicircular density of states in the limit of infinite
dimensions from the point of view of a Landau free energy functional. This
approach provides a simple relation between the free energy of the lattice
model and that of its local description in terms of an impurity model. The
character of the Mott transition in infinite dimensions, (as reviewed by
Georges Kotliar Krauth and Rozenberg, RMP 68, 1996, 13) follows simply from the
form of the free energy functional and the physics of quantum impurity models.
At zero temperature, below a critical value of the interaction U, a Mott
insulator with a finite gap in the one particle spectrum, becomes unstable to
the formation of a narrow band near the Fermi energy. Using the insights
provided by the Landau approach we answer questions raised about the dynamical
mean field solution of the Mott transition problem, and comment on its
applicability to three dimensional transition metal oxides.
