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

自旋热输运现象引起了自旋电子学相关研究的极大兴趣。我们的提案旨在探索不同的铁磁赫斯勒合金薄膜在热诱导自旋输运方面的可用性，以及它们在自旋电子半导体器件中实现的潜力。因此，我们研究了用分子束外延在半导体结构上生长Heusler-alloy薄膜的杂化体系。利用逆自旋霍尔效应，对不同的Heusler合金成分的自旋-塞贝克系数进行了评价。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底层半导体结构的积累。由此产生的自旋扩散和输运在半导体结构将探索横向装置，允许非局部检测自旋扩散。这种方法将漂移从自旋扩散路径中分离出来，因此可以明确地证明与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诱导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.