Photon-assisted quantum coherent phenomena in graphene n-p and n-p-n junctions. Quantum transport in graphene based arrays of nanocrystals

石墨烯 n-p 和 n-p-n 结中的光子辅助量子相干现象。

• 批准号: 173138112
• 负责人: Professor Dr. Konstantin Efetov (†)
• 金额: --
• 依托单位: Institut für Theoretische Physik III: Theoretische Festkörperphysik
• 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 2014-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/173138112?language=en
• 关键词: Photon; assisted; quantum; coherent; phenomena

This project is aimed on a detailed theoretical study of quantum-mechanical effects in the charge transport of graphene based diverse nanostructures. A key point of our proposal is to explore a possibility of coherent photon-assisted quantum interference effects in lateral nanostructures formed in monolayer and bilayer graphene, exposed to an externally applied electromagnetic field (EF). These quantum interference effects result from the combination of two graphene properties: a gapless two bands spectrum of quasiparticles in the graphene and a local resonant interaction of quasiparticles with EF allowing to re-distribute particles between bands. The quantum interference effects manifest themselves, e.g., by large oscillations of photocurrent on the gate voltage. These oscillations present a particular realization of the Ramsey quantum beating ("Ramsey fringes") well known in atomic physics. We will focus also on the quantum phenomena in the transport of graphene based arrays of nanocrystals, i.e. the arrays of quantum dots incorporated in graphene nanoribbons, graphene nanoflakes embedded into an insulator matrix. The quantum effects in such systems are due to interplay of the specific electron spectrum of graphene, quantum-mechanical tunneling between nanocrystals, quantum fluctuations, Coulomb interactions, and disorder. The electronic transport in such systems can vary from the insulator behaviour to a good metal one. We will theoretically study the temperature dependence of the conductivity close to the metal-insulator transition and the co-tunneling regime of linear and nonlinear electronic transport, the gate voltage and magnetic field influence on the transport. The obtained results are important for the fields of Quantum electronics and Quantum information processing in graphene based nanostructures.

该项目旨在对基于石墨烯的不同纳米结构的电荷传输中的量子力学效应进行详细的理论研究。我们的建议的一个关键点是探索在单层和双层石墨烯中形成的横向纳米结构中的相干光子辅助量子干涉效应的可能性，暴露于外部施加的电磁场（EF）。 这些量子干涉效应是由两种石墨烯性质的组合引起的：石墨烯中准粒子的无间隙双带光谱和准粒子与EF的局部共振相互作用，允许在带之间重新分布粒子。量子干涉效应表现出来，例如，通过栅极电压上的光电流的大振荡。这些振荡呈现了原子物理学中众所周知的拉姆齐量子跳动（“拉姆齐条纹”）的特定实现。 我们还将关注基于石墨烯的纳米晶体阵列的传输中的量子现象，即并入石墨烯纳米带中的量子点阵列，嵌入绝缘体基质中的石墨烯纳米片。这种系统中的量子效应是由于石墨烯的特定电子光谱、纳米晶体之间的量子力学隧穿、量子涨落、库仑相互作用和无序的相互作用。在这样的系统中的电子输运可以从绝缘体行为变化到良好的金属行为。我们将从理论上研究接近金属-绝缘体转变的电导率的温度依赖性以及线性和非线性电子输运的共隧穿机制，栅极电压和磁场对输运的影响。 所得结果对于石墨烯基纳米结构的量子电子学和量子信息处理领域具有重要意义。