Raman spectroscopy and low temperature magnetotransport studies on hybrid graphene devices

混合石墨烯器件的拉曼光谱和低温磁输运研究

• 批准号: 173403994
• 负责人: Dr. Jurgen H. Smet
• 金额: --
• 依托单位: Max-Planck-Institut für Festkörperforschung (MPI-FKF)
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2010
• 资助国家: 德国
• 起止时间: 2009-12-31 至 2017-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/173403994?language=en
• 关键词: Raman; spectroscopy; low; temperature; magnetotransport

We intend to continue our investigations of the vibrational and low temperature magneto-transport properties of hybrid graphene devices in order to improve our understanding and scan for correlation phenomena such as broken symmetry states, fractional quantum Hall behaviour and Bose Einstein condensation. We will rely on the transconductance method, which we have identified as very powerful in disclosing gapped or incompressible ground states. We will extend our transport studies to the high density regime using electrolyte gating in order to investigate the consequences of the van Hove singularity in the band structure and verify recent theoretical suggestions that it may be possible to induce superconductivity in graphene at sufficiently high electrostatic doping. These studies will be performed on graphene mono- and bilayers. They will be placed on top of BN using the precision transfer technique developed during the first funding period in order to obtain the highest possible quality for supported devices. For bilayers a twist angle will be introduced as an additional degree of freedom. The twist causes an angle dependent low energy van Hove singularity and therefore represents an important knob to modify the overall electronic bandstructure.In devices based on electrolyte gating, we will also pay attention to electrochemical reactions that may occur at high bias voltages by performing cyclic voltammetry. Even though usually the electrochemistry is considered as undesirable, we consider such measurements interesting all by themselves as they reveal information about the permeation of ions through the graphene sheet. In the case of multilayer graphene, this may be considered as voltage driven intercalation. Our main focus will be on Lithium containing electrolytes.

我们打算继续研究混合石墨烯器件的振动和低温磁输运特性，以提高我们对相关现象的理解和扫描，如对称性破缺态、分数量子霍尔行为和玻色爱因斯坦凝聚。我们将依赖于量子力学方法，我们已经确定它在揭示带隙或不可压缩基态方面非常强大。我们将我们的运输研究扩展到高密度制度，使用电解质门控，以调查的货车霍韦奇异性的带结构的后果，并验证最近的理论建议，它可能是在足够高的静电掺杂诱导石墨烯超导。这些研究将在石墨烯单层和双层上进行。它们将使用在第一个资助期内开发的精密转移技术放置在BN顶部，以获得支持设备的最高质量。对于双层，将引入扭转角作为额外的自由度。扭曲导致一个角度相关的低能量货车霍韦奇异性，因此代表了一个重要的旋钮，以修改整个电子能带结构。在基于电解质门控的器件中，我们还将通过进行循环伏安法来关注在高偏置电压下可能发生的电化学反应。尽管通常电化学被认为是不期望的，但我们认为这种测量本身是有趣的，因为它们揭示了关于离子渗透通过石墨烯片的信息。在多层石墨烯的情况下，这可以被认为是电压驱动的嵌入。我们的主要重点将是含锂电解质。