New sample architectures with Fe-based superconductors based on layer transfer of epitaxial films

基于外延膜层转移的铁基超导体新样品结构

• 批准号: 533424795
• 负责人: Dr. Ruben Hühne
• 金额: --
• 依托单位: Institut für Metallische Werkstoffe
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/533424795?language=en
• 关键词: New; sample; architectures; Fe; based

Fe based superconductors show a rich variety of electronic phases, which can be tuned by doping, pressure or strain. Typically, single crystals are used for detailed studies due to the detrimental effect of the grain boundaries in these materials. Within the last years, high-quality epitaxial thin films were grown in particular for FeSe and BaFe2As2 based materials showing a comparable quality as single crystalline materials. However, the clamping of these superconducting layers on the rigid substrates limits the application of such films for more advanced studies. Therefore, the major aim of this project is to open new pathways for the study of Fe-based superconductors by the realization of thin freestanding layers, which can be transferred to other templates. The central tool for this approach is the application of sacrificial layers, which are mainly used so far for perovskite-based oxide architectures. The main challenge is to optimize these sacrificial layer architectures for the growth, release and transfer of oxygen-free Fe based superconductor films. A key aspect will be the reduction of strain to avoid a high number of cracks during the removal of the sacrificial layer as well as the realization of clean interfaces. Besides the growth of these materials on sacrificial layer architectures, the layer transfer of the grown epitaxial films needs to be studied in detail, which includes the development of suitable etching procedures to avoid any deterioration of the superconducting properties itself as well as of an appropriate transfer strategy to achieve smooth and crack-free films on the new template. Within the project, different applications of the released Fe-based superconducting layers are targeted. At first, layers will be transferred to flexible polymer template to study the influence of strain on the superconducting transition by stretching or bending such templates. Secondly, films will be transferred to thin membranes, which allow to study these materials using a dedicated low-temperature stage inside a transmission electron microscope. Finally, such layers will be used to realize new layer architecture as for example by twisting the layers against each other or by combining the superconductor with other functional materials as magnets or ferroelectrics to create multifunctional heterostructures. In all cases, a proof-of-principle study is mainly targeted in collaboration with experienced partners for the selected applications. We expect that the proposed project creates new opportunities for basic studies on Fe-based superconductors, which might help to understand the mechanism of superconductivity in these materials better. At the same time, the developed approaches will enable the realization of new device architectures for potential applications of Fe-based superconductors in functional heterostructures.

铁基超导体表现出丰富多样的电子相，可以通过掺杂、压力或应变来调谐。由于这些材料的晶界的不利影响，通常使用单晶进行详细的研究。在过去的几年里，高质量的外延薄膜被生长出来，特别是FeSe和BaFe2As2基材料，表现出与单晶材料相当的质量。然而，这些超导层在刚性衬底上的夹紧限制了这些薄膜在更深入研究中的应用。因此，该项目的主要目的是通过实现薄的独立层，为铁基超导体的研究开辟新的途径，这些超导体可以转移到其他模板上。这种方法的核心工具是牺牲层的应用，迄今为止主要用于基于钙钛矿的氧化物结构。主要的挑战是优化这些牺牲层结构，以实现无氧铁基超导体薄膜的生长、释放和转移。一个关键的方面是减少应变以避免在去除牺牲层过程中产生大量裂纹以及实现清洁界面。除了在牺牲层结构上生长这些材料外，还需要详细研究生长的外延薄膜的层转移，包括开发合适的蚀刻程序以避免超导性能本身的任何恶化，以及适当的转移策略以在新模板上获得光滑和无裂纹的薄膜。在该项目中，释放的铁基超导层的不同应用是有针对性的。首先，将层转移到柔性聚合物模板上，通过拉伸或弯曲模板，研究应变对超导转变的影响。其次，将薄膜转移到薄膜上，这样就可以使用透射电子显微镜内的专用低温台来研究这些材料。最后，这些层将用于实现新的层结构，例如通过相互扭曲层或将超导体与其他功能材料（如磁铁或铁电体）结合来创建多功能异质结构。在所有情况下，原理验证研究的主要目标是与选定应用程序的经验丰富的合作伙伴合作。我们期望该项目为铁基超导体的基础研究创造新的机会，这可能有助于更好地理解这些材料的超导机制。同时，所开发的方法将实现新的器件架构，用于铁基超导体在功能异质结构中的潜在应用。