Enhancement of the Spin Accumulation at the Interface Between a Spin-Polarized Tunnel Junction and a Semiconductor

Abstract

We report on spin injection experiments at a Co/Al${}_2$O${}_3$/GaAs interface with electrical detection. The application of a transverse magnetic field induces a large voltage drop $\Delta V$ at the interface as high as 1.2mV for a current density of 0.34 nA.$\mu m^{-2}$. This represents a dramatic increase of the spin accumulation signal, well above the theoretical predictions for spin injection through a ferromagnet/semiconductor interface. Such an enhancement is consistent with a sequential tunneling process via localized states located in the vicinity of the Al${}_2$O${}_3$/GaAs interface. For spin-polarized carriers these states act as an accumulation layer where the spin lifetime is large. A model taking into account the spin lifetime and the escape tunneling time for carriers travelling back into the ferromagnetic contact reproduces accurately the experimental results.

References in corpus (7)

• Direct electronic measurement of the spin Hall effect
• Electrical Detection of Spin Transport in Lateral Ferromagnet-Semiconductor Devices
• Analysis of the Transport Process Providing Spin Injection through an Fe/AlGaAs Schottky Barrier
• Low-temperature spin relaxation in n-type GaAs
• Electrical Detection of Spin Accumulation at a Ferromagnet-Semiconductor Interface
• Semiconductors between spin-polarized source and drain
• Performance of a spin-based insulated gate field effect transistor

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