Influence of oxygen ordering kinetics on Raman and optical response in YBa_2Cu_3O_{6.4}

TL;DR

This study investigates how oxygen ordering kinetics affect the Raman and optical responses in YBa_2Cu_3O_{6.4}, revealing different relaxation times linked to local oxygen arrangements and larger structural formations.

Contribution

It provides new insights into the distinct relaxation dynamics of optical and Raman responses related to oxygen ordering in YBa_2Cu_3O_{6.4}.

Findings

Superconducting T_c and optical conductivity recover slowly, indicating long carrier relaxation times.

Raman scattering relaxes quickly, associated with local oxygen ordering.

Monte Carlo simulations connect relaxation rates to different length scales.

Abstract

Kinetics of the optical and Raman response in YBa_2Cu_3O_{6.4} were studied during room temperature annealing following heat treatment. The superconducting T_c, dc resistivity, and low-energy optical conductivity recover slowly, implying a long relaxation time for the carrier density. Short relaxation times are observed for the B_{1g} Raman scattering -- magnetic, continuum, and phonon -- and the charge transfer band. Monte Carlo simulations suggest that these two relaxation rates are related to two length scales corresponding to local oxygen ordering (fast) and long chain and twin formation (slow).