Biexcitons in Highly Excited CdSe Nanoplatelets

Abstract

We present the phase diagram of free charges (electrons and holes), excitons, and biexcitons in highly excited CdSe nanoplatelets that predicts a crossover to a biexciton-dominated region at easily attainable low temperatures or high photoexcitation densities. Our findings extend previous work describing only free charges and excitons by introducing biexcitons into the equation of state, while keeping the exciton and biexciton binding energies constant in view of the relatively low density of free charges in this material. Our predictions are experimentally testable in the near future and offer the prospect of creating a quantum degenerate, and possibly even superfluid, biexciton gas. Furthermore, we also provide simple expressions giving analytical insight into the regimes of photoexcitation densities and temperatures in which excitons and biexcitons dominate the response of the nanoplatelets.

8 pages, 6 figures

References in corpus (5)

• Strong light-matter coupling in two-dimensional atomic crystals
• Two-dimensional metal-chalcogenide films in tunable optical microcavities
• Photoexcitation of PbS Nanosheets Leads to Highly Mobile Charge Carriers and Stable Excitons
• Explaining Observed Stability of Excitons in Highly Excited CdSe Nanoplatelets
• Effects of Two-Dimensional Material Thickness and Surrounding Dielectric Medium on Coulomb Interactions and Excitons

Cited by in corpus (1)

• Biexciton-like quartet condensates in an electron-hole liquid