The influence of charge and magnetic order on polaron and acoustic phonon dynamics in LuFe2O4

J Lee,D Talbayev,S A Trugman,S.-W Cheong,C L Zhang,X S Xu,A J Taylor,R P Prasankumar,D A Yarotski

doi:10.1063/1.4927739

Abstract

Femtosecond optical pump-probe spectroscopy is used to reveal the influence of charge and magnetic order on polaron dynamics and coherent acoustic phonon oscillations in single crystals of charge-ordered, ferrimagnetic LuFe2O4. We experimentally observed the influence of magnetic order on polaron dynamics. We also observed a correlation between charge order and the amplitude of the acoustic phonon oscillations, due to photoinduced changes in the lattice constant that originate from the photoexcited electrons. This provides insight into the general behavior of coherent acoustic phonon oscillations in charge-ordered materials.

Highlights

Femtosecond optical pump-probe spectroscopy is used to reveal the influence of charge and magnetic order on polaron dynamics and coherent acoustic phonon oscillations in single crystals of charge-ordered, ferrimagnetic LuFe2O4
We observe a fast relaxation component attributed to polaron dynamics that is influenced by the development of spin order, as well as a slower oscillating component that substantially changes across the CO transition
We show that these oscillations are due to the generation of coherent acoustic phonons through the electronic deformation potential, driven by photoinduced changes in the electron temperature

Summary

Introduction

Femtosecond optical pump-probe spectroscopy is used to reveal the influence of charge and magnetic order on polaron dynamics and coherent acoustic phonon oscillations in single crystals of charge-ordered, ferrimagnetic LuFe2O4. We observed a correlation between charge order and the amplitude of the acoustic phonon oscillations, due to photoinduced changes in the lattice constant that originate from the photoexcited electrons.

Results

Conclusion