论文标题
范德华异异性结构中异常层中激子传输的微观起源
Microscopic origin of anomalous interlayer exciton transport in van der Waals heterostructures
论文作者
论文摘要
Van der Waals异质结构构成了研究有趣的多体量子现象的平台。特别是，过渡金属二甲藻（TMD）杂二甲体携带长寿命的层间激子，表现出永久性的平面外偶极矩。在这里，我们开发了一种用于层间激子相互作用的微观理论，包括层间激子的偶极性质及其费米子的子结构，从而产生了有吸引力的费米子交换。我们发现，这些相互作用有助于漂移力，从而在Mose $ _2 $ -WSE $ _2 $异质结构的高度密度上产生了高度非线性激子的传播。我们表明，可以通过更改TMD层之间的HBN垫片数量或调整介电环境来调整传播。特别是，尽管违反直觉，但我们揭示了独立样品中的层间激子比HBN封装的TMDS中的激子慢 - 由于增强了具有更强环境筛选的净库仑饮用的净库仑饮料。总体而言，我们的工作有助于更好地了解技术上有希望的原子薄的半导体中层间激子的传输。
Van der Waals heterostructures constitute a platform for investigating intriguing many-body quantum phenomena. In particular, transition-metal dichalcogenide (TMD) hetero-bilayers host long-lived interlayer excitons which exhibit permanent out-of-plane dipole moments. Here, we develop a microscopic theory for interlayer exciton-exciton interactions including both the dipolar nature of interlayer excitons as well as their fermionic substructure, which gives rise to an attractive fermionic exchange. We find that these interactions contribute to a drift force resulting in highly non-linear exciton propagation at elevated densities in the MoSe$_2$-WSe$_2$ heterostructure. We show that the propagation can be tuned by changing the number of hBN spacers between the TMD layers or by adjusting the dielectric environment. In particular, although counter-intuitive, we reveal that interlayer excitons in free-standing samples propagate slower than excitons in hBN-encapsulated TMDs - due to an enhancement of the net Coulomb-drift with stronger environmental screening. Overall, our work contributes to a better microscopic understanding of the interlayer exciton transport in technologically promising atomically thin semiconductors.
