Strain-Phonon Cooling Effect in hBN Quantum Emitters

Two-dimensional (2D) materials are promising candidates for future quantum technologies due to their tunable properties and atomic-scale thickness. One of their most compelling features is the ability to host single-photon emitters (SPEs), which has been demonstrated in several 2D systems, including hexagonal boron nitride (hBN), offering a platform for quantum photonics. A particularly interesting configuration arises in mechanically strained bubbles formed in 2D materials, where the strain funnels excitons into localized regions, resulting in enhanced and spatially confined photoluminescence. In this work, we reveal that such strain not only affects electronic states but also modifies the local phonon spectrum. We show that mechanical deformation redistributes phonons across the strained region, generating zones of phonon accumulation and depletion. This spatially inhomogeneous phonon landscape leads to what we term strain-phonon cooling—a mechanically-driven modulation of phonon density. We demonstrate this phenomenon in strained hBN bubbles hosting single-photon emitters, offering new avenues into phonon-mediated control of quantum light sources in 2D materials.