FeCoCp3 Molecular Magnets as Spin Filters

P. N. ABUFAGER; R. ROBLES; N. LORENTE

JOURNAL OF PHYSICAL CHEMISTRY C

AMER CHEMICAL SOC

Lugar: Washington; Año: 2015

1932-7447

Metallorganic molecules have been proposed as excellentspin filters in molecular spintronics because of the large spinpolarization of their electronic structure. However, most of the studiesinvolving spin transport have disregarded fundamental aspects such asthe magnetic anisotropy of the molecule and the excitation of spin-flipprocesses during electron transport. Here, we study a moleculecontaining a Co and an Fe atom stacked between three cyclo-pentadienyl rings, which presents a large magnetic anisotropy and aS = 1. These figures are superior to other molecules with the sametransition metal and improves the spin-filtering capacities of the molecule. Nonequilibrium Green?s functions calculations basedon density functional theory predict excellent spin-filtering properties both in tunnel and contact transport regimes. However,exciting the first magnetic state drastically reduces the current?s spin polarization. Furthermore, a difference of temperaturebetween electrodes leads to strong thermoelectric effects that also suppress spin polarization. Our study shows that in principlegood molecular candidates for spintronics need to be confronted with inelastic and thermoelectric effects.