Topological transverse spin, charge and heat transport driven by temperature gradients in transition-metal compounds from first principles

在自旋电子学领域，很明显，必须引入和开发产生和检测自旋极化电荷以及纯自旋电流的新方法。有一种愿景是，在利用各种材料中的热梯度产生的电荷和自旋电流的新范式内，新的进展是可能的。在这个被标记为自旋热电子学的有前途的、完全未被探索的领域的当前发展水平上，任何从真实材料性质的角度的洞察甚至基本水平的理解都是非常有价值的，这可以在密度泛函理论中成功地描述。本项目的目的是定性地了解和定量预测金属铁磁体和顺磁体在外加温度梯度下的横向自旋、电荷和热输运性质。我们的目标是推广和应用在自旋(SHE)和反常霍尔效应(AHE)体系中计算电荷和自旋电导的第一原理方法，并将其应用于这些现象的热模拟研究。后者包括众所周知的实验上但基本上没有被认为是理论上的反常能斯特效应(ANE)，以及最近提出的自旋能斯特效应(SNE)和最近发现的磁振子霍尔效应(MHE)。虽然我们特别关注三维金属中这些现象的出现和晶体各向异性，以及它们在各种类型的表面上的物理性质，这些现象源于具有内在自旋-轨道相互作用的固体中Bloch电子的非平凡拓扑Berry相，但我们特别强调建立和应用第一原理方法来研究具有非平凡交换和Dzyaloshinksii-Moriya相互作用的非共线磁体的横向热输运性质的挑战性任务，已知这些方法对AHE、SHE和MHE的贡献有限。

In the field of spintronics, it became clear that new ways of generating and detecting spinpolarized charge as well as pure spin currents have to be introduced and developed. There is a vision that new advances are possible within the new paradigm of utilizing charge and spin currents generated by thermal gradients in various materials. At the current level of development of this promising and completely unexplored field, tagged as spin caloritronics, any insights or even basic level of understanding from the point of view of properties of real materials, which can be successfully described within the density functional theory, are extremely valuable. The purpose of this project is qualitative understanding and quantitative prediction of transverse spin, charge and heat transport properties of metallic ferromagnets and paramagnets stemming from applied thermal gradients. We aim at extending and applying the first principles methodology for computing the charge and spin conductivities within the setup of spin (SHE) and anomalous Hall effects (AHE), developed over the past years in our group, to studies of thermal analogs of these phenomena. The latter include well-known experimentally, yet basically not considered theoretically anomalous Nernst effect (ANE), as well as recently suggested spin Nernst effects (SNE) and recently discovered magnon Hall effect (MHE). While a particular focus falls on the appearance and crystalline anisotropy of these phenomena in three-dimensional metals, as well as their physics at surfaces of various type, stemming from the non-trivial topological Berry phases of Bloch electrons in solids with intrinsic spin-orbit interaction, we make a particular point on challenging task of establishing and applying of the first-principles methodology for studies of transverse thermal transport properties of non-collinear magnets with non-trivial exchange and Dzyaloshinksii-Moriya interactions, known to provide a finite contribution to the AHE, SHE and MHE.