SL(2, Z) multiplets of type II superstrings in D<10

It has been shown recently that the toroidally compactified type IIB string effective action possesses an SL(2, R) invariance. Using this symmetry we construct an infinite family of macroscopic string-like solutions permuted by SL(2, Z) group for type II superstrings in 4≤D<10. These solutions, which formally look very similar to the corresponding solutions in D=10, are characterized by two relatively prime integers corresponding to the `electricʹ charges associated with the two antisymmetric tensor fields of the strings. Stability of these solutions is discussed briefly in the light of charge conservation and the tension gap equation.