Giant Enhancement of Electron–Phonon Coupling in Dimensionality‐Controlled SrRuO₃ Heterostructures

Abstract

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 SrRuO3 can be largely controlled by multiple intuitive tuning knobs available in synthetic crystals. The coupling strength of quasi‐2D SrRuO3 is enhanced by ≈300‐fold compared with that of bulk SrRuO3. 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.

Coherent Oscillations in a SrRuO3/BiFeO3 Superlattice

“…Recently, it has been proposed that electron–phonon coupling can be controlled by heterostructure engineering in the SrRuO 3 /SrTiO 3 superlattice system [ 25 ]. The reported reflectivity change shows systematic evolution in the relaxation time as a function of the supercell thickness.…”