2025/03/14 by Koch, Katherine A., Rojas-Gatjens, Esteban, Gomez-Dominguez, Martin +3
#FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci)
paper · doi:10.48550/arxiv.2503.11890
Exciton-exciton interactions are fundamental to the light-emitting properties of semiconductors, influencing applications from lasers to quantum light sources. In this study, we investigate the spectroscopic signatures and binding energy of biexcitons in a metal halide two-dimensional Ruddlesden-Popper structure, which is known for hosting distinct excitonic resonances with unique lattice coupling. Using three spectroscopic techniques - photoluminescence (PL) and two variations of two-dimensional electronic spectroscopy (2DES) - we map coherent one-quantum and two-quantum correlations to gain deeper insight into the biexciton characteristics. While PL spectroscopy is hindered by spectral broadening and reabsorption, 2DES provides a more accurate characterization, revealing multiple biexciton states and uncovering a mixed biexciton species arising from exciton cross-coupling. These findings highlight the importance of advanced spectroscopic approaches in accurately determining biexciton binding energies and offer new perspectives on many-body interactions in exciton-polarons within layered perovskites.