AI 中文总结
该研究揭示电荷转移激子的实空间嵌入可生成对称相关非局域复合轨道，在蜂窝晶格中通过 Bethe-Salpeter 方程求解得到拓扑激子平带，为拓扑能带及强关联玻色相提供通用路径。
AI 中文摘要
激子具有单粒子布洛赫粒子所不具备的内部结构，其能带拓扑源于束缚态结构，而非从组成粒子继承而来，这引发了一个问题：束缚态的内部结构如何为激子拓扑提供微观起源。本文中，我们表明电荷转移激子的实空间嵌入可生成与对称性相关的非局域复合轨道的内禀流形，其耦合可支撑拓扑激子能带。横向电子-空穴分离将局域激子嵌入连接其组成位点的键上，而非任一单一位点。我们在蜂窝晶格中演示了该机制，其中三个键中心电荷转移激子轨道形成 Kagome 晶格。通过求解 Bethe-Salpeter 方程，我们表明该涌现的多轨道流形在时间反演对称性破缺时可支撑拓扑激子平带，即便电子和空穴能带在拓扑上是平庸的。所得能带展现出近乎均匀分布的量子几何，有利于相互作用驱动的玻色态。我们的结果为局域复合束缚态的拓扑能带及非常规强关联玻色相建立了通用路径。
英文摘要
Excitons possess internal structure absent from single-particle Bloch particles, allowing their band topology to emerge from the bound-state structure rather than being inherited from their constituents. This raises the question of how the internal structure of a bound state can provide a microscopic origin of exciton topology. Here we show that the real-space embedding of charge-transfer excitons can generate an intrinsic manifold of symmetry-related off-site composite orbitals whose coupling supports topological exciton bands. Lateral electron-hole separation embeds the localized exciton on the bond connecting its constituent sites rather than on either site. We demonstrate this mechanism in a honeycomb lattice, where three bond-centered charge-transfer exciton orbitals form a Kagome lattice. By solving the Bethe-Salpeter equation, we show that this emergent multi-orbital manifold supports a topological exciton flat band upon time-reversal symmetry breaking, even when the electron and hole bands are topologically trivial. The resulting band exhibits nearly uniformly distributed quantum geometry, favorable for interaction-driven bosonic states. Our results establish a general route toward topological bands of localized composite bound states and unconventional strongly correlated bosonic phases.
Comments19 pages, 5 figures
