Tagarelli Fedele, Lopriore Edoardo, Erkensten Daniel, Perea-Causín Raül, Brem Samuel, Hagel Joakim, Sun Zhe, Pasquale Gabriele, Watanabe Kenji, Taniguchi Takashi, Malic Ermin, Kis Andras
Institute of Electrical and Microengineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
Institute of Materials Science and Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
Nat Photonics. 2023;17(7):615-621. doi: 10.1038/s41566-023-01198-w. Epub 2023 Apr 20.
Interactions between out-of-plane dipoles in bosonic gases enable the long-range propagation of excitons. The lack of direct control over collective dipolar properties has so far limited the degrees of tunability and the microscopic understanding of exciton transport. In this work we modulate the layer hybridization and interplay between many-body interactions of excitons in a van der Waals heterostructure with an applied vertical electric field. By performing spatiotemporally resolved measurements supported by microscopic theory, we uncover the dipole-dependent properties and transport of excitons with different degrees of hybridization. Moreover, we find constant emission quantum yields of the transporting species as a function of excitation power with radiative decay mechanisms dominating over nonradiative ones, a fundamental requirement for efficient excitonic devices. Our findings provide a complete picture of the many-body effects in the transport of dilute exciton gases, and have crucial implications for studying emerging states of matter such as Bose-Einstein condensation and optoelectronic applications based on exciton propagation.
玻色气体中面外偶极子之间的相互作用能够实现激子的长程传播。到目前为止,由于缺乏对集体偶极特性的直接控制,限制了可调谐程度以及对激子输运的微观理解。在这项工作中,我们通过施加垂直电场来调制范德华异质结构中激子的层间杂化以及多体相互作用之间的相互影响。通过进行由微观理论支持的时空分辨测量,我们揭示了具有不同杂化程度的激子的偶极相关特性和输运情况。此外,我们发现传输物种的发射量子产率随激发功率保持恒定,其中辐射衰变机制占主导地位,超过非辐射机制,这是高效激子器件的一个基本要求。我们的研究结果提供了稀薄激子气体输运中多体效应的完整图景,对于研究诸如玻色 - 爱因斯坦凝聚等新兴物质态以及基于激子传播的光电子应用具有至关重要的意义。