Hybrid systems consisting of epitaxial Heusler-alloy films on semiconductor structures for spin-caloric applications

自旋热输运现象在自旋电子学相关研究中引起了极大的兴趣。我们的建议旨在探索不同的铁磁Heusler合金薄膜的热诱导自旋输运的可用性，以及它们的潜力，以实现在自旋电子半导体器件。因此，我们研究的混合系统的Heusler合金薄膜生长的半导体结构上的分子束外延。不同的Heusler合金组合物将使用逆自旋霍尔效应对其自旋塞贝克系数进行评估。一旦确定了最有希望的成分，我们将研究自旋的转移及其从铁磁层到下面的半导体结构的积累。在半导体结构中产生的自旋扩散和传输将在横向器件中进行探索，该横向器件允许自旋扩散的非局部检测。这种方法从自旋扩散路径分离率漂移电流，因此允许一个明确的演示自旋相关的输运现象。作为这种全电方法的补充，光学克尔旋转测量将用于验证热致自旋积累的空间分布。此外，自旋发光二极管将用于研究自旋电流注入半导体结构。通过对磁性材料中的磁振子和声子系统的拉曼光谱研究，探讨了导致自旋热输运现象的基本机制。

Spin-caloric transport phenomena have attracted significant interest in spintronics related research. Our proposal aims to explore different ferromagnetic Heusler-alloy films with regard to their usability for heat-induced spin transport as well as their potential to be implemented in spintronic semiconductor devices. Therefore, we investigate hybrid systems with the Heusler-alloy films grown by molecular beam epitaxy on semiconductor structures. Different Heusler alloy compositions will be evaluated with regard to their spin-Seebeck coefficients using the inverse spin Hall effect. Once the most promising compositions have been identified, we will study the transfer of spin and its accumulation from the ferromagnetic layer into the under-lying semiconductor structures. The resulting spin diffusion and transport in the semiconductor structures will be explored in lateral devices which allow for the non-local detection of spin diffusion. This approach sepa-rates drift currents from the spin diffusion path, and hence allows for an unambiguous demonstration of spin-related transport phenomena. Complementary to this all-electrical approach, optical Kerr rotation measurements will be used to verify the spatial distribution of a thermally induced spin accumulation. Furthermore, spin-light emitting diodes will be used to study the injection of spin currents into semiconductor structures. The fundamental mechanisms leading to spin-caloric transport phenomena will be addressed by a Raman spectroscopic study on the magnon and phonon systems in magnetic materials.