Ab initio modeling of spincaloric transport in nanostructered Heusler alloys

本提案的主要目标是提供对自旋热量传输的微观理解，从而为目前对自旋热量效应的现象学描述提供特定材料的支持。我们将对电压偏置或温度梯度驱动下，通过纳米厚度的层状铁磁结构的跨面电输运进行自旋分辨理论研究。特别是，我们的目标是预测当(至少)其中一层由Heusler合金组成时，将观察到大的自旋热量效应。这类有序金属间化合物值得进一步筛选，因为它的一些成员已被证明具有不同寻常的磁性和大的热电系数。所有的电子结构研究将通过第一性原理计算进行，输运将使用原子尺度上的Kubo-Greenwood/Streda形式和更大尺度上的Boltzmann输运方程相结合来研究。计算要解决的一个问题是最近发现的磁热电偶电压及其对样品材料和纳米结构的依赖。

The main goal of the present proposal is to provide a microscopic understanding of spincaloric transport and thus a material-specific underpinning for the present-day phenomenological description of spincaloric effects. We will perform a spin-resolved theoretical study of the cross-plane electrical transport, driven by a voltage bias or a temperature gradient, through layered ferromagnetic structures of nanometer thickness. In particular, we aim at predictions of large spincaloric effects to be observed when (at least) one of the layers consists of a Heusler alloy. This class of ordered intermetallic compounds deserves further screening since some of its members have been shown to exhibit unusual magnetic properties and large thermoelectric coefficients. All electronic structure investigations will be performed by means of first-principles calculations, and transport will be studied using a combination of the Kubo-Greenwood/Streda formalism on the atomic scale and the Boltzmann transport equation on larger scales. One issue to be addressed by the calculations is the recently discovered magneto-thermogalvanic voltage and its dependence on the sample material and nanostructuring.