Tuning vanadium dioxide films by extreme straining - local investigations on transition phenomena and exotic phases

通过极端应变调整二氧化钒薄膜 - 对过渡现象和奇异相的局部研究

基本信息

批准号：
362536548
负责人：
Professor Dr. Jan Ingo Flege
金额：
--
依托单位：
Surface Physics Group
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2017
资助国家：
德国
起止时间：
2016-12-31 至 2020-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/362536548?language=en
关键词：
Tuning vanadium dioxide films extreme

项目摘要

Vanadium dioxide is a correlated oxide with a metal-insulator transition at approximately 340 K. This transition is accompanied by a structural phase transition from the rutile metallic high-temperature structure to the monoclinic insulating low-temperature structure. The transition temperature can be tuned over a broad range by applying mechanical strain; also external electrical fields may drive the transition. Moreover, it is known that under mechanical straining further, exotic phases may occur. Consequently, vanadium dioxide exhibits a large potential for applications, e.g., in oxide electronics provided that these materials properties may be controlled and manipulated as thin films.In this project we investigate simultaneously and in situ the growth and the structural and electronic properties of vanadium dioxide films on ruthenium dioxide surfaces of different orientations by low-energy electron microscopy (LEEM). We exploit the fact that oxidizing the ruthenium surfaces leads to the coexistence of different crystallographically oriented ruthenium dioxide islands that will act as templates in subsequent vanadia growth. The lattice mismatch between vanadia and ruthenia suggests the occurrence of differently and, in some cases, extremely strained vanadia depending on its orientation. Due to this extreme straining, we expect the occurrence of novel, exotic phases and, more generally, a considerably broadened tuning range for the transition temperature of vanadia. These phases will be thoroughly characterized by LEEM and related local diffraction and spectroscopy techniques, including synchrotron-assisted methods. In a parallel effort, we aim to employ scanning probe microscopy to obtain unique insights into small-scale phase separation phenomena and also address, mindful of potential applications, the influence of applied electrical fields. Furthermore, we will extend our studies to ruthenium thin films deposited on sapphire substrates by magnetron sputtering, thereby pushing for higher technological relevance.

二氧化钒是一种与金属 - 胰蛋白的相关氧化物，在大约340 K处。该过渡伴随着从金红石金属金属高温度结构到单层层层次绝缘结构的结构相过渡。通过施加机械应变，可以在广泛的范围内调节过渡温度；外部电场也可能驱动过渡。此外，众所周知，在机械扭曲的进一步紧张下，可能会发生外来阶段。因此，二氧化钒具有巨大的应用潜力，例如，在氧化物电子中，只要可以将这些材料特性作为薄膜控制和操纵。在该项目中，我们同时研究了ruthenium dioxide films in Dioxide corem ruthenium dioxide corem propropy ron-prol-propopy（le-prol-prol-procopre）的生长和结构和电子特性。我们利用了这样一个事实，即氧化钌表面会导致不同晶体学取向的二氧化芳族岛的共存，该岛将在随后的Vanadia生长中充当模板。 Vanadia和Ruthenia之间的晶格不匹配表明其发生不同，在某些情况下，Vanadia极有紧张，具体取决于其方向。由于这种极端的紧张，我们期望新颖的外来相，更普遍地发生了瓦纳迪亚过渡温度的大幅扩展的调谐范围。这些阶段将以LEEM和相关的局部衍射和光谱技术（包括同步辅助方法）的彻底特征。我们旨在采用扫描探针显微镜来获得对小规模相分离现象的独特见解，并考虑到潜在的应用，这是应用电场的影响。此外，我们将通过磁控溅射将研究扩展到沉积在蓝宝石底物上的唯一薄膜，从而推动更高的技术相关性。