Exciton-exciton interaction and biexciton formation in bilayer systems

TL;DR

This paper uses quantum Monte Carlo methods to study biexciton binding energies, exciton interactions, and pair distributions in ideal 2D bilayer systems, revealing stability ranges and exciton identities.

Contribution

It provides new quantum Monte Carlo calculations of biexciton properties in bilayer systems, extending understanding of stability and exciton interactions.

Findings

Biexcitons are stable over a larger range of layer separations.

Excitons retain their identity within biexcitons at large separations.

Calculated exciton-exciton interaction potentials and pair distributions.

Abstract

We report quantum Monte Carlo calculations of biexciton binding energies in ideal two-dimensional bilayer systems with isotropic electron and hole masses. We have also calculated exciton-exciton interaction potentials, and pair distribution functions for electrons and holes in bound biexcitons. Comparing our data with results obtained in a recent study using a model exciton-exciton potential [C. Schindler and R. Zimmermann, Phys. Rev. B \textbf{78}, 045313 (2008)], we find a somewhat larger range of layer separations at which biexcitons are stable. We find that individual excitons retain their identity in bound biexcitons for large layer separations.