Magnetic quantum ratchet in graphene and ratchet effects in graphene with a lateral superlattice

石墨烯中的磁性量子棘轮和具有横向超晶格的石墨烯中的棘轮效应

• 批准号: 173812138
• 负责人: Privatdozent Dr. Jonathan Eroms
• 金额: --
• 依托单位: Institut für Experimentelle und Angewandte Physik
• 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 2016-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/173812138?language=en
• 关键词: Magnetic; quantum; ratchet; graphene; effects

Ratchet effects describe how the periodic motion of particles in a potential with broken symmetry, and subjected to periodic excitation, is converted to directed motion. Here we plan to get insight into the origin of ratchet effects in graphene and to apply them to study the electron dynamics in graphene. This will be studied by considering two model systems. First, the magnetic quantum ratchet, where the combined action of broken symmetry perpendicular to the graphene plane, an in plane magnetic field and excitation with terahertz radiation leads to a dc electric current, as we have shown in recent experiments. While this phenomenon is unambiguously demonstrated experimentally, it is not yet fully understood. We therefore plan to investigate in detail the origin of magnetic quantum ratchet effects in graphene and to apply them to study the symmetry, anisotropy and electron dynamics in this material. The second model system is graphene superimposed by a non-symmetric periodic lateral potential, i.e., breaking the symmetry in the graphene plane. Our recent experiments on THz radiation induced ratchet effect in graphene and semiconductor heterostructures with a one-dimensional lateral potential suggest that lateral superlattices should also lead to ratchet effects in graphene. We plan to investigate terahertz radiation induced ratchet effects in graphene with a periodic modulation systematically and to develop a microscopic picture of this effect. Our investigations should also provide a scientific basis for novel optoelectronic devices for THz radiation.

棘轮效应描述了在对称性破缺的势场中，受到周期性激励的粒子的周期性运动如何转换为定向运动。在这里，我们计划深入了解石墨烯中棘轮效应的起源，并将其应用于研究石墨烯中的电子动力学。这将通过考虑两个模型系统来研究。首先，磁量子棘轮，其中垂直于石墨烯平面的对称性破缺、平面内磁场和太赫兹辐射激发的组合作用导致直流电流，正如我们在最近的实验中所示。虽然这种现象在实验上得到了明确的证明，但还没有完全理解。因此，我们计划详细研究石墨烯中磁量子棘轮效应的起源，并将其应用于研究这种材料的对称性，各向异性和电子动力学。第二模型系统是由非对称周期性横向势叠加的石墨烯，即，打破了石墨烯平面的对称性。我们最近的实验太赫兹辐射诱导棘轮效应在石墨烯和半导体异质结构与一维横向势表明，横向超晶格也应该导致棘轮效应在石墨烯。我们计划研究太赫兹辐射诱导的棘轮效应在石墨烯与周期性调制系统，并开发这种效果的微观图片。我们的研究也将为THz辐射的新型光电器件提供科学依据。