Fig. 4.

Calculations for spin-polarized transport across Ag/vanadocene junctions. a Two junction configurations characterized by perpendicular (left) and parallel (right) molecular orientation with respect to the junction axis. b Spin-resolved transmission versus energy for the two junction configurations. c Spin-resolved projected density of states (PDOS) on the vanadium d orbitals for perpendicular molecular configuration (see also Supplementary Note 10). The PDOS on the rest of the molecule (two carbon rings) is shown in pink. The origin for the different widths of the spin-up and down transmission peaks is discussed in Supplementary Note 11. d Spin-polarization of transmission and vanadium $d_{z^2}$ PDOS (P_T and P_PDOS, respectively) for the perpendicular molecular configuration. Interestingly, P_T remains rather high even at E < −0.5 eV, where P_PDOS is nullified and even changes its sign. e Spin-resolved transmission for different current pathways across the junction in the perpendicular molecular configuration. Two main transmission pathways—across the carbon rings (pink lines) and across the vanadium $d_{z^2}$ level (green lines)—are found to play an essential role interfering destructively (constructively) at the Fermi level for spin-up (down) electrons, as seen by their overall contribution in black dashed lines. The black line describes all contributions (including direct silver-silver tunneling, for example). The origin for the shift in the transmission peaks is discussed in Supplementary Note 12.