Spin-Dependent Molecule Symmetry at a Pentacene-Co Spinterface.

Incorporating spin-polarized scanning tunneling microscopy (SP-STM) measurements and first-principles calculations, we resolve spin-polarized states and consequent features in a pentacene(PEN)-Co hybrid system. Symmetry reduction of PEN clarifies the PEN adsorption site and the Co stacking methods. Near the Fermi energy, the molecular symmetry is spin-dependently recovered and an inversion of spin-polarization in PEN with respect to Co is observed. The experimental findings and calculation results are interpreted by a pz-d hybridization model, in which spin-dependent bonding-antibonding splitting of molecular orbitals happens at metal-organic spinterfaces.