发表机构
University of Maryland, College Park; Universität Heidelberg; Laboratory for Physical Sciences; Brookhaven National Laboratory; National Institute for Materials Science（马里兰大学帕克分校; 海德堡大学; 物理科学实验室; 布鲁海文国家实验室; 物质材料研究机构）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究揭示双层MoTe$_2$具有直接光学带隙，通过电场和掺杂调控层间激子与载流子形成新型费米极化子，为多体量子态研究提供平台。
AI 中文摘要
过渡金属二硫族化物（TMDs）的原子双层结构承载着由层自由度控制的量子相，包括双层维格纳晶体、分数量子霍尔绝缘体和激子凝聚体。这些相主要通过激子光谱学进行探测，然而，在双层体系中，激子与载流子如何相互作用形成费米极化子，其中杂质和费米海均携带层赝自旋，这一问题仍未被充分理解。由于大多数TMD双层具有动量间接光学带隙，非辐射衰减和非均匀展宽掩盖了本征光谱，因此进展受限。在此，我们表明双层MoTe$_2$不同于大多数TMD双层，保留了直接光学带隙，为研究双层费米极化子物理提供了清洁平台。在双栅器件中，垂直电场连续调节层内和层间激子之间的杂化，形成层相干激子。在静电掺杂后，激子光谱演化为多个极化子分支，受载流子掺杂和垂直电场共同控制。其中，我们识别出一种在单层中无类似物的极化子，其中层相干激子被相反层中的载流子所修饰，并被我们的场论模型定量捕获。我们的结果确立了杂质和浴中的赝自旋结构重塑了极化子形成，为层间相干性的玻色-爱因斯坦凝聚体等多体态开辟了新途径。
英文摘要
Atomic bilayers of transition metal dichalcogenides (TMDs) host quantum phases governed by the layer degree of freedom, including bilayer Wigner crystals, fractional Chern insulators, and exciton condensates. These phases are probed primarily through exciton spectroscopy, yet it remains poorly understood how excitons and carriers interact to form Fermi polarons in bilayers, where both the impurity and the Fermi sea carry a layer pseudospin. Progress has been limited because most TMD bilayers have momentum-indirect optical bandgaps, in which non-radiative decay and inhomogeneous broadening obscure the intrinsic spectra. Here, we show that bilayer MoTe$_2$, unlike most TMD bilayers, retains a direct optical bandgap, providing a clean platform for studying bilayer Fermi-polaron physics. In a dual-gated device, an out-of-plane electric field continuously tunes the hybridization between intralayer and interlayer excitons, forming layer-coherent excitons. Upon electrostatic doping, the excitonic spectrum evolves into multiple polaron branches, controlled by both carrier doping and the out-of-plane electric field. Among these, we identify a polaron with no analog in monolayers, in which a layer-coherent exciton is dressed by carriers in the opposite layer, and is quantitatively captured by our field-theoretic model. Our results establish that pseudospin structure in both the impurity and the bath reshapes polaron formation, opening new avenues to many-body states such as Bose-Einstein condensates with interlayer coherence.
Comments16 pages, 4 figures
