Electronic Transport Properties of Spin-Crossover Magnet Fe(II)-N4S2 Complexes

Abstract

Spin-crossover (SCO) magnets can act as one of the most possible building blocks in molecular spintronics due to their magnetic bistability between the high-spin (HS) and low-spin (LS) states. Here, the electronic structures and transport properties through SCO magnet Fe(II)-N4S2 complexes sandwiched between gold electrodes are explored by performing extensive density functional theory calculations combined with non-equilibrium Green's function formalism. The optimized Fe-N and Fe-S distances and predicted magnetic moment of the SCO magnet Fe(II)-N4S2 complexes agree well with the experimental results. The reversed spin transition between the HS and LS states can be realized by visible light irradiation according to the estimated SCO energy barriers. Based on the obtained transport results, we observe nearly perfect spin-filtering effect in this SCO magnet Fe(II)-N4S2 junction with the HS state, and the corresponding current under small bias voltage is mainly contributed by the spin-down electrons, which is obviously larger than that of the LS case. Clearly, these theoretical findings suggest that SCO magnet Fe(II)-N4S2 complexes hold potential applications in molecular spintronics.