Novel device concepts for generating spin currents in graphene

在石墨烯中产生自旋电流的新颖设备概念

• 批准号: 323829711
• 负责人: Dr. Bernd Beschoten
• 金额: --
• 依托单位: II. Physikalisches Institut A - Physik der kondensierten Materie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2016
• 资助国家: 德国
• 起止时间: 2015-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/323829711?language=en
• 关键词: Novel; device; concepts; generating; spin

The ultimate goal of this project is to uncover the intrinsic spin transport properties in single and in few layer graphene. Graphene, a two-dimensional crystal of carbon atoms, is a promising material for exhibiting very long spin diffusion lengths and long electron spin lifetimes, both crucial prerequisites for advanced spintronic devices. As this material only consists of surface atoms particular care and technological knowledge will be needed for addressing its intrinsic properties. To tackle this challenge, we first suggest encapsulating graphene by hexagonal boron nitride from both the top and the bottom sides to allow for best protection against ambient conditions as well as wet chemicals and solvents. In this approach, the electrical contact to graphene shall be established through the outer carbon atoms of the graphene sheet. We expect that this way will allow us to unveil intrinsic spin scattering mechanisms in graphene. Thanks to their high carrier mobility, these structures also enable to study ballistic spin transport phenomena and additionally offer to study the role of edges on spin transport. Secondly, we aim at improving the spin injection and detection barriers by suppressing the formation of conducting pinholes in the oxide barriers in bottom-up non-local spin-valve devices where the graphene layer is mechanically transferred onto predefined Co/MgO electrodes. Thirdly, we suggest exploring methods for controlling the polarization direction of the injected spin current without the need of using external magnetic fields. As electrode material we will use metals which show a strong spin Hall effect with the goal to demonstrate electrical spin injection into graphene by probing the injected spin polarization by neighboring non-local ferromagnetic detectors.

该项目的最终目标是揭示单层和多层石墨烯中的固有自旋输运性质。石墨烯是一种碳原子的二维晶体，是一种有前途的材料，具有很长的自旋扩散长度和长的电子自旋寿命，这两者都是先进自旋电子器件的关键先决条件。由于这种材料仅由表面原子组成，因此需要特别注意和技术知识来解决其内在特性。为了应对这一挑战，我们首先建议从顶部和底部用六方氮化硼封装石墨烯，以最好地保护其免受环境条件以及湿化学品和溶剂的影响。在这种方法中，与石墨烯的电接触应通过石墨烯片的外部碳原子建立。我们希望这种方式将使我们能够揭示石墨烯中固有的自旋散射机制。由于它们的高载流子迁移率，这些结构还能够研究弹道自旋输运现象，并另外提供研究边缘对自旋输运的作用。其次，我们的目标是通过抑制自下而上的非局部自旋阀器件中的氧化物势垒中的导电针孔的形成来改善自旋注入和检测势垒，其中石墨烯层被机械地转移到预定义的Co/MgO电极上。第三，我们建议探索不需要外加磁场就能控制注入自旋电流极化方向的方法。作为电极材料，我们将使用显示出强自旋霍尔效应的金属，目的是通过相邻的非局域铁磁检测器探测注入的自旋极化来证明石墨烯中的电自旋注入。

项目成果

Charge-Induced Artifacts in Nonlocal Spin-Transport Measurements: How to Prevent Spurious Voltage Signals

• DOI: 10.1103/physrevapplied.18.014028
• 发表时间: 2021-12
• 期刊: Physical Review Applied
• 影响因子: 4.6
• 作者: F. Volmer;T. Bisswanger;A. Schmidt;C. Stampfer;B. Beschoten

How to solve problems in micro- and nanofabrication caused by the emission of electrons and charged metal atoms during e-beam evaporation

如何解决电子束蒸发过程中电子和带电金属原子发射引起的微纳加工问题

• DOI: 10.1088/1361-6463/abe89b
• 发表时间: 2021
• 期刊: Journal of Physics D: Applied Physics
• 作者: F. Volmer;I. Seidler;T. Bisswanger;J.-S. Tu;L.R. Schreiber;C. Stampfer;B. Beschoten
• 通讯作者: B. Beschoten

Fractional quantum Hall effect in CVD-grown graphene

• DOI: 10.1088/2053-1583/abae7b
• 发表时间: 2020-10-01
• 期刊: 2D MATERIALS
• 影响因子: 5.5
• 作者: Schmitz, M.;Ouaj, T.;Stampfer, C.
• 通讯作者: Stampfer, C.

Dry-transferred CVD graphene for inverted spin valve devices

• DOI: 10.1063/1.5000545
• 发表时间: 2017-10-09
• 期刊: APPLIED PHYSICS LETTERS
• 影响因子: 4
• 作者: Droegeler, Marc;Banszerus, Luca;Stampfer, Christoph
• 通讯作者: Stampfer, Christoph

Simulations on the gate dependent spin lifetime in graphene non-local spin valve devices

石墨烯非局域自旋阀器件中栅极相关自旋寿命的模拟

• DOI: 10.1002/pssb.201700293
• 发表时间: 2017
• 期刊: arXiv: Mesoscale and Nanoscale Physics
• 作者: M. Drögeler;F. Volmer;C. Stampfer;B. Beschoten
• 通讯作者: B. Beschoten