Fazel Shojaei

Using first-principles calculations, we have investigated the mechanical properties and electronic structures of π–conjugated metal bis(dithiolene) complex sheets (MC4S4), where M = Ni and Pd. First, the sheets are much softer than graphene due to their large porosity. At zero strain, NiC4S4 is a semiconductor with an indirect gap, while PdC4S4 is a metal. Under either biaxial or uniaxial strain, our band structure analysis demonstrates that the band gap of the NiC4S4 slowly decreases to zero with increased strain, which can be attributed to the gradual weakening of π-bonds of the sheet. However, the PdC4S4 becomes a magnetic system beyond the deformation threshold that causes a plastic deformation along the X-axis. In addition, we also observe that both two-dimensional sheets undergo different types of nonreversible plastic changes under the uniaxial strains along the X- and Y-axes.