论文标题
关于基于隧道屏障的电旋转检测器的巨型自旋检测效率的起源
On the origin of the giant spin detection efficiency in tunnel barrier based electrical spin detector
论文作者
论文摘要
自旋信号在主流半导体中的电压有效转化是旋转型的巨大挑战之一。这个过程通常是通过非线性电动传输的铁磁隧道屏障来实现的。在这项工作中，我们证明非线性可能导致旋转电荷转换效率大于10倍的隧道屏障偏振效率的10倍，而后者则在几mV的偏置下。我们确定了导致这种高效自旋检测的基本机制，这是隧道屏障变形和由施加电压的变化导致的导带变化。此外，我们得出了检测器旋转灵敏度的近似分析表达式$ p _ {\ textrm {det}}}（v）$。针对不同屏障形状进行的计算表明，即使主要的机制与屏障类型不同，这种增强也存在于氧化障碍物以及Schottky隧道屏障中。此外，尽管在高温下降低了自旋信号，但它仍然优于线性模型预测的值。我们的发现使对电旋转检测实验的解释和理解开放，并开放了新的路径，以优化自旋传输设备的性能。
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 $P_{\textrm{det}}(V)$. 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.
