Raman scattering studies of spin, charge, and lattice dynamics in Ca_{2-x}Sr_{x}RuO_{4} (0 =< x < 0.2)

TL;DR

This study uses Raman scattering to investigate how spin, charge, and lattice properties evolve in Ca_{2-x}Sr_{x}RuO_{4} as Sr content increases, revealing insights into electron-phonon interactions and phase transitions.

Contribution

It provides new experimental evidence on the effects of Sr substitution on electron-phonon coupling, magnetic excitations, and the metal-insulator transition in Ca_{2-x}Sr_{x}RuO_{4}.

Findings

Increased electron-phonon interaction with Sr doping.

Enhanced temperature dependence of two-magnon features.

Charge gap development and hysteresis indicating a first-order transition.

Abstract

We use Raman scattering to study spin, charge, and lattice dynamics in various phases of Ca_{2-x}Sr_{x}RuO_{4}. With increasing substitution of Ca by Sr in the range 0 =< x < 0.2, we observe (1) evidence for an increase of the electron-phonon interaction strength, (2) an increased temperature-dependence of the two-magnon energy and linewidth in the antiferromagnetic insulating phase, and (3) evidence for charge gap development, and hysteresis associated with the structural phase change, both of which are indicative of a first-order metal-insulator transition (T_{MI}) and a coexistence of metallic and insulating components for T < T_{MI}.