Spin-polarized transport through single-molecule magnet Mn6 complexes

The coherent transport properties of a device, constructed by sandwiching a Mn-6 single-molecule magnet between two gold surfaces, are studied theoretically by using the non-equilibrium Green's function approach combined with density functional theory. Two spin states of such Mn-6 complexes are explored, namely the ferromagnetically coupled configuration of the six Mn-III cations, leading to the S 12 ground state, and the low S = 4 spin state. For voltages up to 1 volt the S = 12 ground state shows a current one order of magnitude larger than that of the S = 4 state. Furthermore this is almost completely spin-polarized, since the Mn-6 frontier molecular orbitals for S = 12 belong to the same spin manifold. As such the high-anisotropy Mn-6 molecule appears as a promising candidate for implementing, at the single molecular level, both spin-switches and low-temperature spin-valves.