Crossover from spin accumulation into interface states to spin injection in the germanium conduction band

Abstract

Electrical spin injection into semiconductors paves the way for exploring new phenomena in the area of spin physics and new generations of spintronic devices. However the exact role of interface states in spin injection mechanism from a magnetic tunnel junction into a semiconductor is still under debate. In this letter, we demonstrate a clear transition from spin accumulation into interface states to spin injection in the conduction band of $n$-Ge. We observe spin signal amplification at low temperature due to spin accumulation into interface states followed by a clear transition towards spin injection in the conduction band from 200 K up to room temperature. In this regime, the spin signal is reduced down to a value compatible with spin diffusion model. More interestingly, we demonstrate in this regime a significant modulation of the spin signal by spin pumping generated by ferromagnetic resonance and also by applying a back-gate voltage which are clear manifestations of spin current and accumulation in the germanium conduction band.

arXiv comment5 pages, 4 figures

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• Efficient Spin Injection into Silicon and the Role of the Schottky Barrier
• Magnetic-Field-Modulated Resonant Tunneling in Ferromagnetic-Insulator-Nonmagnetic junctions
• Large enhancement in the generation efficiency of pure spin currents in Ge using Heusler-compound Co_2FeSi electrodes
• Impurity-assisted tunneling magnetoresistance under weak magnetic field
• How reliable are Hanle measurements in metals in a three-terminal geometry?
• Spin injection and detection in lanthanum- and niobium-doped SrTiO3 using the Hanle technique
• Dynamical Spin Injection into p-type Germanium at Room Temperature
• Spin Transport and Precession in Graphene measured by Nonlocal and Three-Terminal Methods
• Room-temperature spin transport in n-Ge probed by four-terminal nonlocal measurements
• Spin and energy relaxation in germanium studied by spin-polarized direct-gap photoluminescence
• Carrier and Spin Coherent Dynamics in Strained Germanium-Tin Semiconductor on Silicon
• Observation of large spin accumulation voltages in non-degenerate Si spin devices due to spin drift effect: Experiments and theory
• Photoinduced inverse spin Hall effect in Pt/Ge(001) at room temperature
• Giant enhancement of spin detection sensitivity in (Ga,Mn)As/GaAs Esaki diodes
• Non-local opto-electrical spin injection and detection in germanium at room temperature
• Resonant magneto-tunneling between normal and ferromagnetic electrodes in relation to the three-terminal spin transport
• Self-consistent model of spin accumulation magnetoresistance in ferromagnet-insulator-semiconductor tunnel junctions
• Magnetic Mn5Ge3 nanocrystals embedded in crystalline Ge: a magnet/semiconductor hybrid synthesized by ion implantation
• Non-linear spin transport in a rectifying ferromagnet/semiconductor Schottky contact
• Theory of oblique-field magnetoresistance from spin centers in three-terminal spintronic devices