# Spatiotemporal dynamics of Coulomb-correlated carriers in semiconductors

## TL;DR

This paper investigates how Coulomb interactions influence the movement and behavior of excited carriers in advanced semiconductor structures, revealing complex dynamics and the mixture of free and bound states.

## Contribution

It provides an exact wave function analysis of up to two electron-hole pairs, elucidating Coulomb correlation effects in nanometer-scale excitations.

## Key findings

- Coulomb interactions significantly alter carrier wave packet dynamics.
- Excited states are a mixture of free and excitonic components.
- Different effects observed for below and above band-gap excitation.

## Abstract

When the excitation of carriers in real space is focused down to the nanometer scale, the carrier system can no longer be viewed as homogeneous and ultrafast transport of the excited carrier wave packets occurs. In state-of-the-art semiconductor structures like low-dimensional heterostructures or monolayers of transition metal dichalcogenides, the Coulomb interaction between excited carriers becomes stronger due to confinement or reduced screening. This demands a fundamental understanding of strongly interacting electrons and holes and the influence of Coulomb correlations. To study the corresponding particle dynamics in a controlled way we consider a system of up to two electron-hole pairs exactly within a wave function approach. We show that the excited wave packets contain a non-trivial mixture of free particle and excitonic states. We further scrutinize the influence of Coulomb interaction on the wave packet dynamics revealing its different role for below and above band-gap excitation.