Giant Enhancement of Electron-Phonon Coupling in Dimensionality-Controlled SrRuO 3 Heterostructures.

Electrons in crystals interact closely with quantized lattice degree of freedom, determining fundamental electrodynamic behaviors and versatile correlated functionalities. However, the strength of the electron-phonon interaction is so far determined as an intrinsic value of a given material, restricting the development of potential electronic and phononic applications employing the tunable coupling strength. Here, it is demonstrated that the electron-phonon coupling in SrRuO can be largely controlled by multiple intuitive tuning knobs available in synthetic crystals. The coupling strength of quasi-2D SrRuO is enhanced by ≈300-fold compared with that of bulk SrRuO . This enormous enhancement is attributed to the non-local nature of the electron-phonon coupling within the well-defined synthetic atomic network, which becomes dominant in the limit of the 2D electronic state. These results provide valuable opportunities for engineering the electron-phonon coupling, leading to a deeper understanding of the strongly coupled charge and lattice dynamics in quantum materials.