Spin Filtering Induced by Quantum Interference and Weak Interfacial Spin Polarization

Destructive quantum interference (DQI) is an intriguing phenomenon in molecular devices known for ultralow conductance. A consequent prospect is the spin filtering induced by spin splitting of DQI features. Here we demonstrate that in magnetic DQI molecular junctions consisting of acene molecules and ferromagnetic electrodes, a weak magnetic proximity effect (MPE) on molecular ends may induce a distinct spin splitting of DQI dips in spite of the subtle spin splitting of eigenstates. The mechanism analysis reveals an additional contribution from spin splitting of wave functions, which comes out as a result of the coexistence of MPE and the electron-electron interaction. The results of model calculations are further verified by first-principles calculations. This work provides a strategy to achieve efficient spin filtering at low bias without large intrinsic magnetic moments or strong magnetic fields and opens a new arena for spin-dependent DQI in molecular spintronics.