Quantum siphoning of finely spaced interlayer excitons in reconstructed MoSe2/WSe2 heterostructures

TL;DR

This study demonstrates persistent quantum confinement in reconstructed MoSe2/WSe2 heterostructures, revealing multiple interlayer exciton states and a novel 'quantum siphoning' phenomenon with implications for quantum sensing.

Contribution

It uncovers quantum confinement effects and cascade transitions in reconstructed heterostructures, introducing the concept of quantum siphoning in exciton dynamics.

Findings

Multiple finely-spaced interlayer exciton states (~1 meV separation) identified.

Observation of cascade-like transitions from a single potential well.

Transient suppression and recovery of emission termed 'quantum siphoning'.

Abstract

Atomic reconstruction in twisted transition metal dichalcogenide heterostructures leads to mesoscopic domains with uniform atomic registry, profoundly altering the local potential landscape. While interlayer excitons in these domains exhibit strong many-body interactions, extent and impact of quantum confinement on their dynamics remains unclear. Here, we reveal that quantum confinement persists in these flat, reconstructed regions. Time-resolved photoluminescence spectroscopy uncovers multiple, finely-spaced interlayer exciton states (~ 1 meV separation), and correlated emission lifetimes spanning sub-nanosecond to over 100 nanoseconds across a 10 meV energy window. Cascade-like transitions confirm that these states originate from a single potential well, further supported by calculations. Remarkably, at high excitation rates, we observe transient suppression of emission followed by gradual recovery, a process we term "quantum siphoning". Our results demonstrate that quantum confinement and competing nonlinear dynamics persist beyond the ideal moire paradigm, potentially enabling applications in quantum sensing and modifying exciton dynamics via strain engineering.