Giant enhancement of the electron-phonon coupling in dimensionality-controlled SrRuO₃ heterostructures

Electrons in the crystals closely interact with quantized lattice degree of freedom, determining fundamental electrodynamic behaviors and versatile correlated functionalities. Meanwhile, the strength of the electron-phonon interaction is usually determined as an intrinsic value for a given material. Here we demonstrate that the electron-phonon coupling in SrRuO₃ can be largely controlled by multiple knobs available in synthetic crystal structure. The coupling strength of quasi-2D SrRuO₃ is enhanced by about three-hundred-fold compared to that of bulk SrRuO₃. The giant enhancement of the electron-phonon coupling strength is attributed to a non-local nature of the coupling within the well-defined synthetic atomic network, which becomes predominant in the limit of two-dimensional electronic state. Our results provide valuable opportunities to engineer the electron-phonon coupling, leading to a deeper understanding of various novel phenomena observed in quantum materials