Spin-Dependent Charge Transport in Single Chiral-Molecule Junctions

The experimental observation that electrons transferred through a chiral molecule favors a particular electronic spin orientation is known as the chiral-induced spin selectivity (CISS) effect. This effect has been extensively studied both experimentally and theoretically. However, the mechanism of this effect is still not fully understood. Here, we report on spin filtering by molecular junctions based on a single pi-conjugated chiral molecule suspended between a nickel electrode and a non-ferromagnetic electrode. The effect depends on the molecule chirality, applied voltage polarity, and the non-ferromagnetic metal type. We ascribe our observations to the CISS effect at the quantum coherent transport regime and discuss the influence of the electrode properties on the CISS effect.