论文标题
莫伊尔（Moiré）潜力的激子运输：从跳跃到分散体制
Exciton transport in a moiré potential: from hopping to dispersive regime
论文作者
论文摘要
对TMD单层中激子的传播已经进行了深入的研究，揭示了有趣的多粒子作用，例如光环形成和非经典扩散。最初的研究研究了扭曲的TMD双层的激子运输如何变化，包括库仑排斥和类似哈伯德的激子跳跃。在这项工作中，我们调查了跳跃方向向有效释放激子的分散性制度的扭曲依赖性转变。基于在莫伊尔电势存在下的激子的微观方法，我们表明跳跃状态的角度最高为大约2°的角度，并且由哈伯德模型很好地描述。然而，由于越来越多的离域激子状态，哈伯德模型在很大角度上失败了。在这里，具有有效质量的游离颗粒的量子机械分散决定了激子的传播。总体而言，我们的工作为扭曲的范德华异质结构中激子传播的特征提供了微观见解。
The propagation of excitons in TMD monolayers has been intensively studied revealing interesting many-particle effects, such as halo formation and non-classical diffusion. Initial studies have investigated how exciton transport changes in twisted TMD bilayers, including Coulomb repulsion and Hubbard-like exciton hopping. In this work, we investigate the twist-angle-dependent transition of the hopping regime to the dispersive regime of effectively free excitons. Based on a microscopic approach for excitons in the presence of a moiré potential, we show that the hopping regime occurs up to an angle of approximately 2° and is well described by the Hubbard model. At large angles, however, the Hubbard model fails due to increasingly delocalized exciton states. Here, the quantum mechanical dispersion of free particles with an effective mass determines the propagation of excitons. Overall, our work provides microscopic insights into the character of exciton propagation in twisted van der Waals heterostructures.
