Nonlinear Spin Current and Magnetoresistance of Molecular Tunnel Junctions
Нелинейный спиновый ток и магнитосопротивление молекулярных туннельных переходов
2006-04-26
SCID: 54.1/pq8a6kym
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Density functional theoryKeldysh nonequilibrium Green's functionMagnetoresistanceMolecular tunnel junctionsNonlinear spin current
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Abstract (AI)
We report on a theoretical study of spin-polarized quantum transport through a Ni-bezenedithiol(BDT)-Ni molecular magnetic tunnel junction (MTJ). Our study is based on carrying out density functional theory within the Keldysh nonequilibrium Green's function formalism, so that microscopic details of the molecular MTJ are taken into account from first principles. A magnetoresistance ratio of approximately 27% is found for the Ni-BDT-Ni MTJ which declines toward zero as bias voltage is increased. The spin currents are nonlinear functions of bias voltage, even changing sign at certain voltages due to specific features of the coupling between molecular states and magnetic leads.
Key Findings
1
Magnetoresistance decreases toward zero as the applied bias voltage increases.
2
Spin currents depend nonlinearly on bias voltage and can reverse sign at specific voltages.
3
Spin-current reversals arise from particular coupling features between molecular states and the magnetic nickel leads.
4
The calculated magnetoresistance ratio is approximately 27% at low bias for the Ni-BDT-Ni junction.
5
The study models spin-polarized quantum transport in a Ni-benzenedithiol-Ni molecular magnetic tunnel junction using first-principles DFT combined with nonequilibrium Green’s functions.
Research Object
Ni-benzenedithiol (BDT)-Ni molecular magnetic tunnel junction
Research Subject
Bias-dependent nonlinear spin-polarized quantum transport, including spin-current reversal and magnetoresistance
Publication Details
Publication Date
2006-04-26
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