Topological Exciton Dynamics in Strain-Engineered Lead Halide Perovskite Quantum Dots

The manipulation of quantum states via mechanical strain has been shown unlocked new paradigms in condensed matter physics, yet the emergence of strain induced topological excitons in soft quantum materials remains unexplored. Here, we show that helical strain transforms lead halide perovskite quantum dots (QDs) into a platform for topological excitonics. Using a first-principles-informed framework combining strain-modulated Lamé eigenstates and non-perturbative Coulomb interactions, we identify a strain-driven topological transition at critical ellipticity k=0.59±0.02, marked by inversion of the exciton Chern number (C=0→1) and π-Berry phase accumulation. Our model predicts a >3× enhancement of exciton binding energy (up to 42 ± 3 meV) through dimensional crossover in quasi-1D confinement, sufficient for room-temperature quantum coherence. Anomalous transport regimes emerge, including nonlinear group velocity scaling (v_g ∼k^1.7) and strain-activated dark states that defy conventional effective mass descriptions. These findings are verifiable via torsional strain microscopy and time-resolved Berry interferometry and align with recent reports of anomalous exciton diffusion in CsPbBr₃ nanowires. Our results position perovskite QDs as the first solution-processable system hosting topologically protected excitons, paving the way for fault-tolerant quantum light sources, reconfigurable exciton devices, and chiral photonic interfaces. The discovery of strain-tunable topological phases bridges nanomechanics with quantum photonics, offering a new dimension for quantum state engineering beyond rigid semiconductor platforms.