Spin transport through a junction entirely consisting of molecules from first principles

Abstract

Using first-principles calculations based on density functional theory combined with the nonequilibrium Green's function formalism, we studied the spin transport through a single molecular junction which consists of a single 1,4-benzenedithiolate (BDT) molecule and two ferromagnetic electrodes [(Ge5)Fe]∞. A large magnetoresistance ratio (MR) of 21100% was found in the [(Ge5)Fe]∞-BDT-[(Ge5)Fe]∞ molecular junction at small bias voltage, and the MR value decreased with the increase in the applied bias voltage. For the parallel magnetization configuration, the molecular junction showed outstanding spin injection effects. Negative differential resistance was observed for the antiparallel magnetization configuration. Spin dependent transmission spectra at different bias voltages were used to explain the calculated results.