Speaker
Description
In many two-dimensional semiconductors, spatially varying strain profiles provide a powerful means to induce and steer exciton motion, yet a predictive microscopic description of the resulting dynamics remains limited. Here, we present a general first-principles framework for exciton dynamics in inhomogeneous materials. Our approach combines GW-BSE calculations of strain-dependent excitonic band structures with a continuous position- and momentum-dependent potential landscape, thereby coupling real-space and reciprocal-space dynamics within a unified description.
We demonstrate the framework for the representative case of two-dimensional materials, focusing on the illustrative limit of propagation in the absence of scattering. More broadly, however, the method is not restricted to 2D systems and can be naturally extended to materials of any dimensionality, as well as to additional interaction channels and scattering mechanisms whenever the relevant quantities are available on compatible momentum- or real-space grids.
Applying the approach to representative strain profiles in 2D transition-metal dichalcogenide monolayers, we qualitatively reproduce experimentally observed phenomena such as directed exciton drift toward regions of higher strain, as well as nontrivial transport and broadening behavior that provide a microscopic interpretation of previously reported anomalous drift and diffusion. These results show how band-structure renormalization and local strain gradients jointly govern exciton transport, and establish a versatile route for predicting and engineering quasiparticle dynamics in 2D materials and beyond.