Dynamics of electron-electron correlated to electron-phonon coupled phase progression in trilayer nickelate La4Ni3O10

TL;DR

This study uses Raman spectroscopy to investigate the phase transition in trilayer nickelate La4Ni3O10, revealing a shift from electron-phonon to electron-electron correlated phases around 150 K, with implications for understanding superconductivity.

Contribution

It provides detailed insights into the phase transition mechanisms in La4Ni3O10, highlighting the change in electron correlations and phonon dynamics across the charge density wave transition.

Findings

Transition from electron-phonon to electron-electron correlated phase below T*

Suppression of electron-phonon coupling by ~70% at T*

Emergence of zone folded phonon modes indicating charge density wave phase

Abstract

Trilayer nickelates are a rich class of materials exhibiting diverse correlated phenomena, including superconductivity, density wave transitions, non-Fermi liquid behavior along with an unusual metal-to-metal transition around T* ~ 150 K. Understanding the electronic correlations, lattice and charge dynamics are crucial to unreveal the origin of superconductivity and other instabilities in nickelates. Our in-depth Raman measurements shows that trilayer nickelate, La4Ni3O10, shows transition from electron-phonon coupled phase to the electron-electron correlated one below charge density wave transition around T* with an estimated energy gap of ~ 18-20 meV. The transition around T* is also accompanied by the emergence of zone folded phonon modes reflecting the transition into the charge density wave phase. Phonon modes self-energy parameters show anomalous changes around T* attributed to the electron-electron correlations, and renormalization rate of the phonon modes is much slower in the charge-ordered phase compared to the phase above T*. The transition around T* are marked by the suppression of electron-phonon coupling parameter by ~ 70 %, a change of the quasiparticle dynamics from non-Fermi liquid to the Landau-Fermi liquid type behaviour estimated using the low frequency Raman response.