Exploring the low energy excitations of the S=1 quasi-1D molecular system Mo3S7(dmit)3

The molecular magnetic system Mo3S7(dmit)3 is a semiconductor with a charge gap of around 100 K and no magnetic transition or spin freezing down to 2 K. In the crystal structure the molecules include closely coupled ligand triangles and these triangular units are arranged in hexagonal layers. Theoretical studies indicate that each of the molecular triangles has spin 1 and that the in-plane coupling between triangles is very weak compared to the inter-plane coupling. The system can thus be viewed as a strong-rung three-leg spin ladder which is expected to behave as a symmetry-protected topological phase with a Haldane spin gap on the order of 1 K. muSR studies in longitudinal fields up to 2.4 T will be used to test this picture by observing the changes in the temperature dependent relaxation rate that are expected to take place when the Haldane gap is closed by the magnetic field.