Binding energies of trions and biexcitons in layered semiconductors from diffusion quantum Monte Carlo calculations*

Excitonic effects play a key role in the optoelectronic behavior of layered materials semiconductors (LM-S). To facilitate the interpretation of experimental photoabsorption and photoluminescence spectra we provide statistically exact diffusion quantum Monte Carlo binding energy (BE) data for Mott-Wannier models of excitons, trions, and biexcitons in LM-S. We also provide interpolation formulas giving the BE and contact density as functions of the electron and hole effective masses and in-plane polarizability. Our results suggest that experimental spectra have been misclassified, because the trion BE should exceed the biexciton BE, but they also indicate that the Keldysh interaction fails to give a quantitative description of the observed excitonic properties of LM-S. The contact pair density data that we provide will enable the theoretical and experimental exploration of the role played by contact interactions between charge carriers and intervalley scattering in LM-S [1].
[1] M. Szyniszewski, E. Mostaani, N. D. Drummond, and V. I. Fal’ko, Phys.Rev. B 95, 081301 (2017).