QUANTUM GROUP-APPROACH TO A SOLUBLE VERTEX MODEL WITH GENERALIZED ICERULE

Using the representation of the quantum group SL(q)(2) by the Weyl ope rators of the canonical commutation relations in quantum mechanics, we construct and solve a new vertex model on a square lattice. Random va riables on horizontal bonds are Ising variables, and those on the vert ical bonds take half positive integer values. The vertex is subjected to a generalized form of the so-called ''ice rule,'' its property is s tudied in detail and its free energy calculated with the method of qua ntum inverse scattering. Remarkably. in analogy with the usual six-ver tex model, there exists a ''free-fermion'' limit with a novel rich ope rator structure. The existing algebraic structure suggests a possible connection with a lattice neutral plasma of charges, via the fermion-b oson correspondence.