Ab initio calculation of the bias-dependent transport properties of Mn12 molecules

The bias-dependent transport properties of a device constructed by sandwiching a Mn-12 single molecule magnet between gold electrodes are investigated within an ab initio framework combining the nonequilibrium Green's function approach with density-functional theory. The self-consistently calculated current-voltage, I-V, curves exhibit characteristic negative differential resistances. These originate from the interplay between electron localization and the rehybridization of the Mn-12 molecular levels in an external electric field. Interestingly, such features in the transport are sensitive to the internal spin configuration of the molecule. This may therefore enable one to infer the internal spin state of the molecule from a detailed knowledge of the I-V.