3 research outputs found
Anomalous dispersion of longitudinal optical phonons in oxygen-doped La2−xSrxCuO4+δ
Inelastic neutron scattering has been used to study the in-plane Cu-O
bond-stretching mode in oxygen doped LaSrCuO () and LaCuO (). Similar to
results from optimally doped LaSrCuO (), we observe anomalous features in the dispersion of this
half-breathing mode in the form of a softening halfway through the Brillouin
Zone. Considering the differences in electronic structure and local environment
between the oxygen- and strontium-doped compounds with similar , we
rule out a connection between the phonon anomaly and structural instabilities
related to the specific dopant type. We interpret the phonon anomaly as a
signature of correlated charge fluctuations possibly connected to stripes.Comment: 6 pages, 4 figures, Supplemental Materia