Low temperature dynamic polaron liquid in a manganite exhibiting colossal magnetoresistance

Abstract

Polarons - fermionic charge carriers bearing a strong companion lattice deformation - exhibit a natural tendency for self-localization due to the recursive interaction between electrons and the lattice. While polarons are ubiquitous in insulators, how they evolve in transitions to metallic and superconducting states in quantum materials remains an open question. Here, we use resonant inelastic x-ray scattering (RIXS) to track the electron-lattice coupling in the colossal magneto-resistive bi-layer manganite La${}_{1.2}$Sr${}_{1.8}$Mn${}_2$O${}_7$ across its metal-to-insulator transition. The response in the insulating high-temperature state features harmonic emissions of a dispersionless oxygen phonon at small energy transfer. Upon cooling into the metallic state, we observe a drastic redistribution of spectral weight from the region of these harmonic emissions to a broad high energy continuum. In concert with theoretical calculations, we show that this evolution implies a shift in electron-lattice coupling from static to dynamic lattice distortions that leads to a distinct polaronic ground state in the low temperature metallic phase - a dynamic polaron liquid.

References in corpus (5)

• Polaron Coherence Condensation as the Mechanism for Colossal Magnetoresistance in Layered Manganites
• Resonant inelastic x-ray scattering study of hole-doped manganites La1-xSrxMnO3 (x=0.2 and 0.4)
• Lattice coupling and Franck-Condon effects in K-edge resonant inelastic X-ray scattering
• Non-gapped Fermi surfaces, quasiparticles and the anomalous temperature dependence of the near-$E_F$ electronic states in the CMR oxide La${}_{2-2x}$Sr${}_{1+2x}$Mn${}_2$O${}_7$ with $x=0.36$
• A Minimal tight-binding model for ferromagnetic canted bilayer manganites

Cited by in corpus (4)

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• Orbital inversion and emergent lattice dynamics in infinite layer CaCoO${}_2$
• The influence of phonon symmetry and electronic structure on the electron-phonon coupling momentum dependence in cuprates
• Excitations across the equilibrium and photoinduced `hidden' states of magnetoresistive manganites