# Binding energies of trions and biexcitons in two-dimensional semiconductors from diffusion quantum Monte Carlo calculations

## TL;DR

This paper provides highly accurate diffusion quantum Monte Carlo data on the binding energies of excitons, trions, and biexcitons in 2D semiconductors, aiding interpretation of experimental spectra and understanding of charge interactions.

## Contribution

It offers the first statistically exact binding energy data for 2D semiconductor models, along with interpolation formulas for various material parameters.

## Key findings

- Trion binding energies are generally larger than biexciton binding energies.
- Contact pair densities enable perturbation theory descriptions of exchange interactions.
- Interpolation formulas relate binding energies to effective masses and polarizability.

## Abstract

Excitonic effects play a particularly important role in the optoelectronic behavior of two-dimensional (2D) semiconductors. To facilitate the interpretation of experimental photoabsorption and photoluminescence spectra we provide statistically exact diffusion quantum Monte Carlo binding-energy data for Mott-Wannier models of excitons, trions, and biexcitons in 2D semiconductors. We also provide contact pair densities to allow a description of contact (exchange) interactions between charge carriers using first-order perturbation theory. Our data indicate that the binding energy of a trion is generally larger than that of a biexciton in 2D semiconductors. We provide interpolation formulas giving the binding energy and contact density of 2D semiconductors as functions of the electron and hole effective masses and the in-plane polarizability.