Spin-dependent electronic transport through a porphyrin ring ligating an Fe(II) atom:: An ab initio study

Conductance calculations employing density functional theory methodology and Landauer formalism predict that a ligated iron atom can be used as a switching device. The iron atom is ligated in our models by a porphyrin molecule. The iron-porphyrin molecular device is shown to lose more than 66% of its conductance by shifting from the low spin coupling state to excited spin states. Further reduction is also correlated with a mechanical distortion of the porphyrin plane. Both the distortions and spin transitions are fast processes that can be invoked by manipulating the iron's ligation scheme through the axial ligands.