Unusual Lattice Dilation and Strong Electron-Phonon Coupling in Erbium Ferrite Perovskite

Abstract

Most materials in Nature expand when heated, and very limited materials show the opposite behavior, i.e., negative thermal expansion (NTE). Here, we observed that NTE is associated with the rarely occurring Fano antiresonance in Raman spectroscopy and investigated the role of electron-phonon coupling on the negative thermal expansion observed in the multiferroic ErFeO3 perovskite

for this purpose, the temperature-dependent synchrotron-based X-ray diffraction and Raman scattering experiments were carried out in the temperature range 80-300 K. The occurrence of NTE was also confirmed via the strain gauge measurement technique. A one-to-one correlation between strong electron-phonon coupling, as reflected in the Fano antiresonance in Raman spectra, with q ≈ 0, and the geometrical rotation of the Fe-O-Fe bond angle that has been observed. It has been demonstrated that the NTE is controlled by the strong temperature dependence of electron-phonon coupling in the prepared ErFeO3 sample. The present report may provide a new strategy for manipulating NTE behaviors by tuning the electron-phonon coupling. © 2024 American Chemical Society.