论文标题
过渡金属二甲基元素单层和范德华异质结构中的激子 - 外激体相互作用
Exciton-exciton interaction in transition metal dichalcogenide monolayers and van der Waals heterostructures
论文作者
论文摘要
由于库仑相互作用很强，激发子在2D材料中主导了激发动力学。尽管对电子之间的库仑散射进行了充分的研究，但激子的相互作用更具挑战性，还有待探索。作为由电子和孔组成的中性复合玻色子，激子显示出非平凡的散射动力学。在这里，我们研究了过渡金属元素化和相关的范德华异质结构中的显微基础基础激子相互作用。我们证明，有效散射的关键标准是大型电子/孔质量不对称，导致了激子的内部电荷不均匀性，并强调了它们的cobosonic子结构。此外，增强的激子BOHR RADII增强了交换和直接的激子相互作用。我们还预测了通常与声子驱动的散射相关的意外温度依赖性，并且由于其永久性偶极矩，我们揭示了层间激子的相互作用的数量级更强。开发的方法可以推广到任意材料系统，并将有助于研究密切相关的激子系统，例如Moire Super Lattices。
Due to a strong Coulomb interaction, excitons dominate the excitation kinetics in 2D materials. While Coulomb-scattering between electrons has been well studied, the interaction of excitons is more challenging and remains to be explored. As neutral composite bosons consisting of electrons and holes, excitons show a non-trivial scattering dynamics. Here, we study on microscopic footing exciton-exciton interaction in transition-metal dichalcogenides and related van der Waals heterostructures. We demonstrate that the crucial criterion for efficient scattering is a large electron/hole mass asymmetry giving rise to internal charge inhomogeneities of excitons and emphasizing their cobosonic substructure. Furthermore, both exchange and direct exciton-exciton interactions are boosted by enhanced exciton Bohr radii. We also predict an unexpected temperature dependence that is usually associated to phonon-driven scattering and we reveal an orders of magnitude stronger interaction of interlayer excitons due to their permanent dipole moment. The developed approach can be generalized to arbitrary material systems and will help to study strongly correlated exciton systems, such as moire super lattices.
