AI 中文总结
研究超周期性、准周期性和无序对石墨烯系统电子及自旋输运的影响，用大规模实空间量子输运方法，分析魔角扭曲双层石墨烯等，揭示输运与多种因素关系，确定准晶序特征及自旋输运情况，统一呈现相关输运现象。
AI 中文摘要
本论文研究超周期性、准周期性和无序如何塑造基于石墨烯的系统中的电子和自旋输运，重点关注与实验相关的长度尺度和实际原子模型。使用大规模实空间量子输运方法，首先建立了可控制的输运指纹，以区分周期性结构中的传统布洛赫传播和准周期调制引起的异常动力学。在此框架基础上，分析了魔角扭曲双层石墨烯，发现在有限无序窗口内，适度的安德森无序可反常增强平均自由程。这种无序诱导的离域化还与从光导率提取的量子度量变化有关，揭示了输运、电子几何结构和底层态实空间范围之间的直接联系。接着研究了石墨烯准晶体近似物和混合多层堆叠，确定了亚弹道输运和自相似局域化模式为准晶序的特征，同时也证明了它们对无序和层间邻近效应的强脆弱性。最后探讨了悬浮单层石墨烯中的自旋输运，表明原子尺度的波纹会产生短程波动的Rashba场，即使电荷输运接近弹道，也能将自旋寿命限制在纳秒范围内。这些结果提供了一个统一的图景，说明几何结构、无序和结构复杂性如何控制扭曲和波纹石墨烯系统中的输运现象。
英文摘要
This thesis investigates how superperiodicity, quasiperiodicity, and disorder shape electronic and spin transport in graphene-based systems, with an emphasis on experimentally relevant length scales and realistic atomistic modeling. Using large-scale real-space quantum-transport methods, it first establishes controlled transport fingerprints that distinguish conventional Bloch propagation in periodic structures from the anomalous dynamics induced by quasiperiodic modulations. Building on this framework, the thesis analyzes magic-angle twisted bilayer graphene and shows that, within a finite disorder window where flat-band features remain robust, moderate Anderson disorder can counterintuitively enhance the mean free path. This disorder-induced delocalization is further linked to changes in the quantum metric extracted from optical conductivity, revealing a direct connection between transport, electronic geometry, and the real-space extent of the underlying states. The study then turns to graphene quasicrystal approximants and hybrid multilayer stacks, identifying sub-ballistic transport and self-similar localization patterns as signatures of quasicrystalline order, while also demonstrating their strong fragility against disorder and interlayer proximity effects. Finally, the thesis addresses spin transport in suspended monolayer graphene, showing that atomic-scale corrugations generate short-range fluctuating Rashba fields that can limit spin lifetimes to the nanosecond range even when charge transport remains close to ballistic. Taken together, these results provide a unified picture of how geometry, disorder, and structural complexity govern transport phenomena in twisted and corrugated graphene systems.
Comments195 pages, 47 figures, PhD thesis
