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Coherent transport through spin-croosover single molecules.

Coherent transport through spin-croosover single molecules


D. Aravena, E. Ruiz.
J. Am. Chem. Soc., 134, (2012) 777.

The silicon-based technology is reaching the limits of critical size, where quantum effects have an impact on the proper functioning of the devices. This has led scientists to devise new devices that exploit quantum phenomena in their design. In this context, the magnetic molecules have attracted considerable attention due to some properties of these systems; such as spin transitions and unimoleculars magnets can serve as basis for new molecular spintronics devices. We recently presented the results of DFT calculations combined with non-equilibrium Green’s functions, which can predict the response of electric current to a voltage applied to a device composed of a spin transition molecule, trans-bis (isothiocyanate) iron (II), connected to two gold electrodes. We found that the total current depends on the spin of the molecule. This property is related to the energy of the d orbitals in the FeII center in both spin states and shows that the conductance is deeply linked to the electronic rearrangement due to the spin transition. In the case of high-spin molecules, we have found that the current has a spin polarized character, with most of the conductance due to β electrons, acting as a spin filter device. This result is also linked to the splitting of d orbitals of FeII cation and should be a general feature of complex devices based on FeII  systems with spin transition behavior.