Ferromagnetic GaN based structures for room temperature spintronics: spin dynamics and spin interactions

在SQUID测量中观察到GaN：Gd甚至GaN：Cu的铁磁性仍不是很清楚。我们将对磁光Kerreffect进行敏感的静态测量，以检查这种(体模)铁磁性是否对导带有影响，以及它是否可用于自旋对准装置。我们将继续对纤锌矿GaN基材料的自旋弛豫进行时间分辨测量，以探索提高自旋寿命的异质结构。这些研究将扩展到GaN的亚稳立方相，在那里我们将对立方GaN量子阱和超晶格进行第一次测量，这是由于我们最近发现的体相c-GaN在室温下的ns自旋寿命。我们的初步结果表明，立方GaN中存在一些悬而未决的问题，如弱的温度依赖性或强的自旋寿命空间变化。我们计划将µ光致发光数据与自旋寿命数据和时间分辨光致发光测量进行空间关联，以阐明立方结构中曾经存在的六方夹杂的影响。

The observation of ferromagnetism of GaN:Gd and even GaN:Cu in SQUID measurements is still not well understood. We will perform sensitive static measurements of the magnetooptical Kerreffect to check if this (phantom) ferromagnetism has an influence on the conduction band and if it may be useful for applications in spin aligners. We will continue our time-resolved measurements on spin relaxation in wurtzite GaN based materials to explore heterostructures for improved spin lifetimes. These studies will be extended to the metastable cubic phase of GaN, where we will perform the first measurements on cubic GaN quantum wells and superlattices motivated by our recent findings of ns-spinlifetimes in bulk c-GaN at room temperature. Our preliminary results indicate open questions in cubic GaN like a weak temperature dependence or strong spatial variations of the spin lifetime. We plan spatial correlation of µ-photoluminescence data with spin lifetime data and time-resolved photoluminescence measurements to clarify e.g. the influence of the ever present hexagonal inclusions in cubic structures.