Nonlinear spin transport in a rectifying ferromagnet/semiconductor Schottky contact

Jansen, R.; Spiesser, A.; Saito, H.; Yuasa, Shinji

doi:10.1103/physrevb.92.075304

Cited by 7 publications

(3 citation statements)

References 55 publications

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“…Another point of view focuses on the nonlinear currentvoltage characteristic of the tunnel barrier itself [45,46]. A simple analysis suggests that the ratio of the detected voltage to the spin accumulation should be modified by the ratio (J/V )/(dJ/dV ) of the absolute to differential conductance, although Jansen et al [47] have noted that this correction factor is in fact an upper bound. In our case, however, we observe an effect that is opposite to that suggested by this argument.…”

Section: A Effect Of Detector Biasmentioning

confidence: 99%

Spin injection and detection up to room temperature in Heusler alloy/n-GaAs spin valves

et al. 2016

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We have measured the spin injection efficiency and spin lifetime in Co2FeSi/n-GaAs lateral nonlocal spin valves from 20 to 300 K. We observe large (∼40 µV) spin valve signals at room temperature and injector currents of 10 3 A/cm 2 , facilitated by fabricating spin valve separations smaller than the 1 µm spin diffusion length and applying a forward bias to the detector contact. The spin transport parameters are measured by comparing the injector-detector contact separation dependence of the spin valve signal with a numerical model accounting for spin drift and diffusion. The apparent suppression of the spin injection efficiency at the lowest temperatures reflects a breakdown of the ordinary drift-diffusion model in the regime of large spin accumulation. A theoretical calculation of the D'yakonov-Perel spin lifetime agrees well with the measured n-GaAs spin lifetime over the entire temperature range. arXiv:1610.03797v1 [cond-mat.mes-hall]

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Section: A Effect Of Detector Biasmentioning

confidence: 99%

Spin injection and detection up to room temperature in Heusler alloy/n-GaAs spin valves

et al. 2016

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“…To make continuous progress in Sibased spintronics and to take full advantage of current CMOS technology, there is an urgent need to develop Si-based spintronics devices [20,21]. In this work we demonstrate electrical detection of spin transport in a 2DEG in a Si/SiGe MODQW using FM Mn-germanosilicide (Mn(Si 0.7 Ge 0.3 ) x ) Schottky [18,22] end contacts, which is a new approach to circumvent the difficulty of etching process adopted for the typical spin valve devices [4,7]. The experiments show that the spin-polarized electrons could be laterally injected into one side of the 2DEG confined at the Si/SiGe interface, and subsequently detected from the other side by the magnetoresistance (MR) of a FM/Si/FM spin valve.…”

Section: Introductionmentioning

confidence: 98%

Electrical detection of spin transport in Si two-dimensional electron gas systems

et al. 2016

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Spin transport in a semiconductor-based two-dimensional electron gas (2DEG) system has been attractive in spintronics for more than ten years. The inherent advantages of high-mobility channel and enhanced spin-orbital interaction promise a long spin diffusion length and efficient spin manipulation, which are essential for the application of spintronics devices. However, the difficulty of making high-quality ferromagnetic (FM) contacts to the buried 2DEG channel in the heterostructure systems limits the potential developments in functional devices. In this paper, we experimentally demonstrate electrical detection of spin transport in a high-mobility 2DEG system using FM Mn-germanosilicide (Mn(Si0.7Ge0.3)x) end contacts, which is the first report of spin injection and detection in a 2DEG confined in a Si/SiGe modulation doped quantum well structure (MODQW). The extracted spin diffusion length and lifetime are l sf = 4.5 μm and [Formula: see text] at 1.9 K respectively. Our results provide a promising approach for spin injection into 2DEG system in the Si-based MODQW, which may lead to innovative spintronic applications such as spin-based transistor, logic, and memory devices.

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“…This amplification effect offers an interesting perspective for on-chip integration of spin-based circuits and has attracted considerable attention from theoretical standpoint. Indeed, various tentative mechanisms were proposed over the recent years to explain the observed large spin detection efficiency, such as two-step tunneling [16], thermionic emission [17] or lateral current inhomogeneity [18], to name just a few. Unfortunately, none of the above mentioned mechanisms seems to satisfactorily account for all the experimental findings.…”

Section: Introductionmentioning

confidence: 99%

On the origin of the giant spin detection efficiency in tunnel barrier based electrical spin detector

Fourneau,

Silhanek,

Nguyen

2020

Preprint

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Efficient conversion of a spin signal into an electric voltage in mainstream semiconductors is one of the grand challenges of spintronics. This process is commonly achieved via a ferromagnetic tunnel barrier where non-linear electric transport occurs. In this work, we demonstrate that non-linearity may lead to a spin-to-charge conversion efficiency larger than 10 times the spin polarization of the tunnel barrier when the latter is under bias of a few mV. We identify the underlying mechanisms responsible for this remarkably efficient spin detection as the tunnel barrier deformation and the conduction band shift resulting from a change of applied voltage. In addition, we derive an approximate analytical expression for the detector spin sensitivity Pdet(V ). Calculations performed for different barrier shapes show that this enhancement is present in oxide barriers as well as in Schottky tunnel barriers even if the dominant mechanisms differs with the barrier type. Moreover, although the spin signal is reduced at high temperatures, it remains superior to the value predicted by the linear model. Our findings shed light into the interpretation and understanding of electrical spin detection experiments and open new paths to optimize the performance of spin transport devices.

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Nonlinear spin transport in a rectifying ferromagnet/semiconductor Schottky contact

Cited by 7 publications

References 55 publications

Spin injection and detection up to room temperature in Heusler alloy/n-GaAs spin valves

Spin injection and detection up to room temperature in Heusler alloy/n-GaAs spin valves

Electrical detection of spin transport in Si two-dimensional electron gas systems

On the origin of the giant spin detection efficiency in tunnel barrier based electrical spin detector

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