Biexciton Binding Energy Landscape (2D)

This is the 2D counterpart to the 3D biexciton-binding-energy quantum dot simulator. It runs the exact same schematic physics — an exciton and biexciton competing between direct Coulomb attraction and many-body exchange/correlation repulsion inside a confined dot — but shows it through two 2D-native panels instead of a 3D orbiting-particle scene: a true planar cross-section of carriers doing a confined random walk inside a lateral disk-shaped dot, and a live R-vs-ΔXX binding-energy landscape curve that makes the entire bound/antibound size crossover visible at once, with a marker tracking the live radius and shaded regions showing where the biexciton line redshifts (bound) or blueshifts (antibound) of twice the exciton energy. A live accumulated photoluminescence spectrum at the bottom shows the same X/XX peak separation measured in real colloidal quantum dot spectroscopy.