AI 中文总结
研究揭示双层激子凝聚体中存在由电子-空穴关联驱动的隐藏量子几何效应，其二阶极化响应与序参量呈平方反比标度，为非线性物理研究提供了新平台。
AI 中文摘要
当电子掺杂层与空穴掺杂层堆叠且载流子密度近似相等时，层间库仑相互作用会将双层系统转化为激子凝聚体（EC）。在本研究中，我们揭示了双层EC的一项基本性质：即使非相互作用能带是平凡的，激子序也会在关联电子-空穴能带中产生非平凡的隐藏量子几何效应。这种由EC驱动的特殊量子几何表现为，对双层EC系统施加面内交流电场时会出现特征性的面外极化响应。特别地，二阶响应与双层EC序参量呈现特征性的平方反比标度关系。我们的发现揭示了由电子-空穴关联驱动的一种基本隐藏贝里相位效应，并确立双层EC是开展丰富非线性物理研究的有前景平台。
英文摘要
When an electron-doped layer is stacked with a hole-doped layer with approximately equal carrier density, inter-layer Coulomb interaction turns the bilayer system into an exciton condensate (EC). In this Letter, we reveal a fundamental property of bilayer ECs: the excitonic order gives rise to nontrivial hidden quantum geometric effects in the correlated electron-hole bands, even when the non-interacting bands are trivial. Such peculiar EC-driven quantum geometry manifests itself in a characteristic out-of-plane polarization response upon applying an in-plane AC electric field to the bilayer EC system. In particular, the second-order response exhibits a characteristic inverse square scaling with the bilayer EC order parameter. Our finding reveals a fundamental hidden Berry phase effect driven by electron-hole correlations, and establishes bilayer EC as a promising platform for rich nonlinear physics.
CommentsMaintext: 6 pages, 2 figures; Supplemental material: 5 pages
