Abstract
In two-dimensional hybrid organic-inorganic metal-halide perovskites, the intrinsic optical lineshape reflects multiple excitons with distinct binding energies, each dressed differently by the hybrid lattice. Given this complexity, a fundamentally far-reaching issue is how Coulomb-mediated many-body interactions --- elastic scattering such as excitation-induced dephasing, inelastic exciton bimolecular scattering, and multi-exciton binding --- depend upon the specific exciton-lattice coupling. We report the intrinsic and density-dependent exciton pure dephasing rates and their dependence on temperature by means of a coherent nonlinear spectroscopy. We find exceptionally strong screening effects on multi-exciton scattering relative to other two-dimensional single-atomic-layer semiconductors. Importantly, the exciton-density dependence of the dephasing rates is markedly different for distinct excitons. These findings establish the consequences of particular lattice dressing on exciton many-body quantum dynamics, which critically define fundamental optical properties that underpin photonics and quantum optoelectronics in relevant exciton density regimes.
Highlights
In two-dimensional hybrid organic-inorganic metal-halide perovskites, the intrinsic optical line shape reflects multiple excitons with distinct binding energies [1,2], each dressed differently by the hybrid lattice [3]
We quantify the role of many-body elastic scattering effects on exciton dephasing rates in two-dimensional hybrid metal-halide perovskites by means of nonlinear coherent excitation spectroscopy at a temperature of 5 K
We find that the exciton-density dependence of excitation-induced dephasing (EID) is two to three orders of magnitude lower than in other atomic monolayer semiconductors such as transition metal dichalchogenides
Summary
Dephasing rates are very sensitive probes of the consequences of lattice dressing effects on excitons These are challenging to extract directly from linear optical probes such as absorption or photoluminescence spectroscopy given that the experimental linewidths typically arise from two distinct but coexisting contributions: homogenous and inhomogenous broadening [see Fig. 1(a)]. While the former is due to dephasing and is governed by the intrinsic finite lifetime of excited states and by dynamic disorder, the latter is caused by a statistical distribution of the transition energy due to static disorder, defects, or grain boundaries. Four distinct excitons (labeled A, A , B, and B*) are observed about 200 meV below the continuum band edge
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