Phonon Signature of Charge Inhomogeneity in High Temperature Superconductors YBa2Cu3O{6+x}

TL;DR

This study uses inelastic neutron scattering to reveal how charge inhomogeneity in YBa2Cu3O{6+x} varies with temperature and doping, highlighting phonons' role in charge dynamics of high-temperature superconductors.

Contribution

It provides direct experimental evidence of temperature-dependent charge inhomogeneity and its impact on phonons in high-Tc superconductors, a novel insight into their charge dynamics.

Findings

Charge doping increases the volume of charged regions without changing local charge density.

Charge inhomogeneity becomes more pronounced below the superconducting transition temperature.

Phonon response magnitude indicates strong involvement in charge dynamics.

Abstract

Temperature and composition dependences of high-energy longitudinal optical (LO) phonons in YBa2Cu3O{6+x}, studied by inelastic neutron scattering measurements, provide clear evidence for temperature dependent spatial inhomogeneity of doped charges. The measurements indicate that charge doping increases the volume fraction of the charged regions, while the local charge density remains unchanged. For the optimally doped sample the charge distribution changes sharply near the superconducting transition temperature, with stronger charge inhomogeneity below Tc. The remarkable magnitude of the phonon response to charge suggests strong involvement of phonons in charge dynamics.