Ring-shaped luminescence patterns in a locally photoexcited electron-hole bilayer

TL;DR

This paper uses molecular dynamics simulations to explore how high photoexcitation power causes ring-shaped luminescence patterns and predicts novel phenomena like electron density oscillations and phase transitions in electron-hole bilayers.

Contribution

It introduces a detailed simulation study revealing the formation of luminescence rings and predicts new dynamical behaviors in electron-hole bilayer systems.

Findings

Ring-shaped luminescence patterns form at high excitation power.

Stationary spatial oscillations of electron density are predicted.

A dynamical phase transition occurs in electron cloud expansion.

Abstract

We report the results of molecular dynamics simulation of a spatiotemporal evolution of the locally photoexcited electrons and holes localized in two separate layers. It is shown that the ring-shaped spatial pattern of luminescence forms due to the strong in-layer Coulomb interaction at high photoexcitation power. In addition, the results predict (i) stationary spatial oscillations of the electron density in quasi one-dimensional case and (ii) dynamical phase transition in the expansion of two-dimensional electron cloud when threshold electron concentration is reached. A possible reason of the oscillations and a theoretical interpretation of the transition are suggested.