Finite-temperature correlations for the U-q(sl(2 vertical bar 1))-invariant generalized Hubbard model

We study an integrable model of one-dimensional strongly correlated electro ns at finite temperature by explicit calculation of the correlation lengths of various correlation functions. The model is invariant with respect to t he quantum superalgebra U-q(s[(2\1)) and characterized by the Hubbard inter action, correlated hopping and pair-hopping terms. Using the integrability, the graded quantum transfer matrix is constructed. From the analyticity of its eigenvalues, a closed set of nonlinear integral equations is derived w hich describe the thermodynamical quantities and the finite-temperature cor relations. The results show a crossover from a regime with dominating densi ty-density correlations to a regime with dominating superconducting pair co rrelations. Analytical calculations in the low-temperature limit are also d iscussed.