Spin-filtering effect in highly coherent molecular spin-qubits

We investigate the spin-dependent electronic transport properties of various V-based spin-qubit complexes, namely [VL$_3$]$^{2-}$ (L = $\alpha$-C$_3$S$_5$, $\beta$-C$_3$S$_5$ and $\beta$- C$_3$S$_4$O). This class of molecules, made almost completely by ions without nuclear spins, shows the highest spin-coherence times ever found. Using a well-established non-equilibrium Green function approach coupled to density functional theory we are able to determine the spin-filtering properties of such organic complexes when placed in a nanojunction with (111)-oriented Au electrodes. The influence of the anchor atom on the transport properties, as well as the geometrical-isomer effects of the substituents, are here addressed. Remarkably, one of the complexes is found to act as a very efficient spin-filter over a wide range of applied voltage.