Trilayer and Superlattice Half Metal Thin Films

三层和超晶格半金属薄膜

• 批准号: 1232275
• 负责人: Ching Yao Fong
• 金额: $ 40万
• 依托单位: University of California-Davis
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-08-15 至 2016-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1232275&HistoricalAwards=false
• 关键词: Trilayer; Superlattice; Half; Metal; Thin

Intellectual Merit:There has been intense interest in silicon based spintronic materials, particularly half-metals, for room temperature device applications. In previous studies, half-metallicity has been predicted in thin films of Mn-doped Si. However, the Mn atoms need to occupy the energetically costly substitutional sites that require breaking of Si-Si bonds. This bond breaking process has been the major obstacle for achieving this class of materials that may take advantage of the mature Si technology. Very recently, the PI has predicted half-metallicity in two Mn/Si/Mn trilayers with Mn concentration at 0.5 monolayer and occupying the energetically favorable interstitial sites, and a 0.5 monolayer hole doping in the spacer layer. These exciting results suggest that half metallic Si-based trilayers and their related superlattices are within reach. This project combines theoretical and experimental efforts to design and realize such trilayer and superlattice pseudo-spin valves of silicon-based half-metal in thin film forms. The search for the ideal half-metallic trilayers and superlattices in ferromagnetic or antiferromagnetic phases, and modifications of existing algorithms to treat transport properties for proposed pseudo-spin valves will provide new knowledge concerning magnetism and electronic properties in layered structures. Doping in the Si spacer layer will be used to enhance the magnetic coupling between the two Mn layers. New algorithms of magnetic susceptibility will allow accurate determination of Curie temperature in any magnetic systems. Structural, magnetic, and magneto-transport measurements will be performed in order to characterize the fabricated structures and compare their properties with theoretical predictions. The use of silicon-based materials would enable rapid development of technological applications for spintronic devices. The synergy of the theoretical and experimental efforts is expected to facilitate the optimal design and fabrication of these novel devices.Broader Impacts:The proposed pseudo-spin valves are expected to exhibit new and intriguing half-metallic properties, which are highly relevant for the development of novel spintronic devices, such as sensors, switches, magnetic memory, and logic devices. Furthermore, new understandings will be gained on: (i) how can the hole doping between two layers of transition metal elements cause the half metallicity and couple the magnetic moments between Mn layers in the trilayers and superlattices? (ii) unique new knowledge about manipulating growth parameters to obtain samples of Si-based trilayer and superlattice pseudo-spin valves with predicted properties by the synthesis method. These advancements will significantly facilitate future developments of spintronic devices. The PIs will actively recruit underrepresented minority students to work with them. They have collaborations with research groups in the US, as well as in Sweden, Germany, China, Spain and Turkey. Graduate students will have the opportunity to interact with leading researchers in the field nationally, as well as internationally. The PIs also strive to integrate research with educational and outreach activities to enhance the learning experience of students from junior high school through graduate school.

智力优点：人们对用于室温器件应用的硅基自旋电子材料，特别是半金属产生了浓厚的兴趣。 在之前的研究中，已经预测了锰掺杂硅薄膜的半金属性。然而，Mn原子需要占据能量昂贵的取代位点，这需要破坏Si-Si键。这种键断裂过程一直是实现此类可利用成熟硅技术的材料的主要障碍。最近，PI预测了两个Mn/Si/Mn三层的半金属性，其中Mn浓度为0.5单层并占据能量上有利的间隙位置，并且间隔层中的空穴掺杂为0.5单层。这些令人兴奋的结果表明半金属硅基三层及其相关的超晶格是可以实现的。该项目结合了理论和实验工作，设计并实现了薄膜硅基半金属的三层和超晶格赝自旋阀。寻找铁磁或反铁磁相中理想的半金属三层和超晶格，以及修改现有算法来处理拟自旋阀的输运特性，将提供有关层状结构中的磁性和电子特性的新知识。 Si 间隔层中的掺杂将用于增强两个 Mn 层之间的磁耦合。新的磁化率算法将允许准确测定任何磁性系统中的居里温度。将进行结构、磁性和磁输运测量，以表征制造的结构并将其特性与理论预测进行比较。硅基材料的使用将使自旋电子器件的技术应用快速发展。理论和实验工作的协同作用有望促进这些新颖器件的优化设计和制造。更广泛的影响：所提出的伪自旋阀预计将表现出新的、有趣的半金属特性，这与开发高度相关新型自旋电子器件，如传感器、开关、磁存储器和逻辑器件。此外，还将获得新的理解：（i）两层过渡金属元素之间的空穴掺杂如何引起半金属性并耦合三层和超晶格中Mn层之间的磁矩？ （ii）关于操纵生长参数以通过合成方法获得具有预测特性的硅基三层和超晶格赝自旋阀样品的独特新知识。这些进步将极大地促进自旋电子器件的未来发展。 PI 将积极招募代表性不足的少数族裔学生与他们一起工作。他们与美国、瑞典、德国、中国、西班牙和土耳其的研究小组合作。研究生将有机会与国内外该领域的领先研究人员互动。 PI 还努力将研究与教育和推广活动结合起来，以增强初中生到研究生院学生的学习体验。

项目成果

Structural and magnetic depth profiles of magneto-ionic heterostructures beyond the interface limit

超出界面极限的磁离子异质结构的结构和磁性深度剖面

• DOI: 10.1038/ncomms12264
• 发表时间: 2016-07-22
• 期刊: Nature Communications
• 影响因子: 16.6
• 作者: D. Gilbert;A. Grutter;E. Arenholz;Kai Liu;Brian J. Kirby;J. Borchers;B. Maranville
• 通讯作者: B. Maranville

Chiral Majorana fermion modes in a quantum anomalous Hall insulator–superconductor structure

量子反常霍尔绝缘体-超导体结构中的手性马约拉纳费米子模式

• DOI: 10.1126/science.aag2792
• 发表时间: 2016-06-18
• 期刊: Science
• 影响因子: 56.9
• 作者: Q. He;L. Pan;Alex Stern;E. Burks;X. Che;G. Yin;Jing Wang;Biao Lian;Quan Zhou;E. Choi
• 通讯作者: E. Choi

Realization of ground-state artificial skyrmion lattices at room temperature

室温基态人造斯格明子晶格的实现

• DOI: 10.1038/ncomms9462
• 发表时间: 2015-10-08
• 期刊: Nature Communications
• 影响因子: 16.6
• 作者: Gilbert DA;Maranville BB;Balk AL;Kirby BJ;Fischer P;Pierce DT;Unguris J;Borchers JA;Liu K
• 通讯作者: Liu K

Controllable positive exchange bias via redox-driven oxygen migration

通过氧化还原驱动的氧迁移实现可控的正交换偏压

• DOI: 10.1038/ncomms11050
• 发表时间: 2016-03-21
• 期刊: Nature Communications
• 影响因子: 16.6
• 作者: Gilbert DA;Olamit J;Dumas RK;Kirby BJ;Grutter AJ;Maranville BB;Arenholz E;Borchers JA;Liu K
• 通讯作者: Liu K