Enormous Lifetime Variations and Anomalous Nonlinear Dynamics of Interlayer Excitons in Reconstructed MoSe2/WSe2 Heterostructures.

Atomic reconstruction in twisted transition metal dichalcogenide heterostructures leads to mesoscopic domains with a uniform atomic registry, profoundly altering the local potential landscape. While interlayer excitons in these domains exhibit strong many-body interactions, the extent and impact of quantum confinement on their dynamics remains unclear. We reveal that quantum confinement persists in these flat, reconstructed regions. Time-resolved photoluminescence spectroscopy uncovers multiple, finely spaced (∼1 meV) interlayer exciton states and correlated emission with enormous lifetime variation from subnanosecond to over 100 ns across a 10 meV energy-window. Cascade-like transitions confirm that these states originate from reconstructed domains acting as potential wells, further supported by calculations. At high excitation rates, we observe anomalous nonlinear dynamics, specifically transient photoluminescence suppression followed by gradual recovery, a phenomenon we term "quantum siphoning". Our results demonstrate that quantum confinement and nonlinear dynamics persist beyond ideal moiré paradigm, potentially enabling applications in sensing and modifying dynamics via strain engineering.