近日，瑞士洛桑联邦理工大学的Andras Kis课题组与德国马尔堡大学的Ermin Malic等人合作，成功实现了范德华异质结构中杂化激子输运的电控制。相关研究成果已于2023年4月20日在国际知名学术期刊《自然—光子学》上发表。

在这项研究中，通过施加垂直电场，研究人员成功地调制了范德华异质结中激子的层状混杂和多体相互作用。通过微观理论支持的时空分辨测量，他们揭示了具有不同混杂程度的激子的偶极依赖性质和输运情况。此外，他们还发现输运组分的发射量子产额随激发功率变化而保持不变，发射机制中辐射衰减占主导地位，这是有效激子器件所必需的。该项研究结果为稀薄激子气体输运中的多体效应提供了完整的图像，并对研究玻色-爱因斯坦凝聚和基于激子传播的光电应用等新兴物态具有重要意义。

据了解，平面外偶极在玻色气体中能够促进激子的长程传播。然而，目前对于集体偶极性质的直接控制还不够充分，这限制了激子输运的可调谐性和微观理解。

附：英文原文

Title: Electrical control of hybrid exciton transport in a van der Waals heterostructure

Author: Tagarelli, Fedele, Lopriore, Edoardo, Erkensten, Daniel, Perea-Causn, Ral, Brem, Samuel, Hagel, Joakim, Sun, Zhe, Pasquale, Gabriele, Watanabe, Kenji, Taniguchi, Takashi, Malic, Ermin, Kis, Andras

Issue&Volume: 2023-04-20

Abstract: 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.

DOI: 10.1038/s41566-023-01198-w

Source: https://www.nature.com/articles/s41566-023-01198-w