Voltage tuning of thermal spin current in ferromagnetic tunnel contacts to semiconductors
Voltage tuning of thermal spin current in ferromagnetic tunnel contacts to semiconductors
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DOI：
10.1038/nmat3869
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发表时间：
2014-04-01
期刊：
影响因子：
41.2
通讯作者：
Jansen, Ron
中科院分区：
文献类型：
--
作者：
Jeon, Kun-Rok;Min, Byoung-Chul;Jansen, Ron
自旋电流对于控制基于自旋的存储器、逻辑器件和微波器件中铁磁元件的磁化以及在非磁性材料中诱导自旋极化是至关重要的。产生自旋电流的一种独特方法是利用热梯度和热流。在这里，我们证明了热自旋电流可以通过电压方便地调谐。在与半导体（硅和锗）的磁隧道触点中，研究表明，适度的电压（类似于200 mV）将塞贝克自旋隧穿引起的热自旋电流改变了五倍，因为它改变了相关的隧穿状态，从而改变了自旋相关的热电参数。自旋电流的大小和方向也可以通过将电自旋电流和热自旋电流相结合来调制。结果表明，与费米能量无关的自旋相关的热电特性是可以获得的，这为通过电压而不是材料设计来定制热自旋电流和扭矩开辟了道路。
Spin currents are paramount to manipulate the magnetization of ferromagnetic elements in spin-based memory, logic and microwave devices, and to induce spin polarization in non-magnetic materials. A unique approach to create spin currents employs thermal gradients and heat flow. Here we demonstrate that a thermal spin current can be tuned conveniently by a voltage. In magnetic tunnel contacts to semiconductors (silicon and germanium), it is shown that a modest voltage (similar to 200 mV) changes the thermal spin current induced by Seebeck spin tunnelling by a factor of five, because it modifies the relevant tunnelling states and thereby the spin-dependent thermoelectric parameters. The magnitude and direction of the spin current is also modulated by combining electrical and thermal spin currents with equal or opposite sign. The results demonstrate that spin-dependent thermoelectric properties away from the Fermi energy are accessible, and open the way towards tailoring thermal spin currents and torques by voltage, rather than material design.