Knorr Willy, Brem Samuel, Meneghini Giuseppe, Malic Ermin
Department of Physics, Philipps University, 35037 Marburg, Germany.
Nanoscale. 2024 May 9;16(18):8996-9003. doi: 10.1039/d4nr00136b.
Twisted transition metal dichalcogenides (TMDs) present an intriguing platform for exploring excitons and their transport properties. By introducing a twist angle, a moiré superlattice forms, providing a spatially dependent exciton energy landscape. Based on a microscopic many-particle theory, we investigate in this work polaron-induced changes in exciton transport properties in the exemplary MoSe/WSe heterostructure. We demonstrate that polaron formation and the associated enhancement of the moiré exciton mass lead to a significant band flattening. As a result, the moiré inter-cell tunneling and the propagation velocity undergo noticeable temperature and twist-angle dependent changes. We predict a reduction of the hopping strength ranging from 80% at a twist angle of 1° to 30% at 3° at room temperature. The provided microscopic insights into the spatio-temporal exciton dynamics in presence of a moiré potential further expand the possibilities to tune charge and energy transport in 2D materials.
扭曲的过渡金属二卤化物（TMDs）为探索激子及其输运性质提供了一个有趣的平台。通过引入扭曲角，形成了莫尔超晶格，提供了一个空间依赖的激子能量景观。基于微观多粒子理论，我们在这项工作中研究了极化子对典型MoSe/WSe异质结构中激子输运性质的影响。我们证明，极化子的形成以及与之相关的莫尔激子质量的增强导致了能带的显著扁平化。结果，莫尔晶胞间隧穿和传播速度经历了明显的温度和扭曲角依赖变化。我们预测，在室温下，跳跃强度将从1°扭曲角时的80%降低到3°扭曲角时的30%。所提供的关于存在莫尔势时的时空激子动力学的微观见解进一步扩展了调控二维材料中电荷和能量输运的可能性。
