Zusammenfassung
Inelastic neutron scattering measurements of La1.85Sr0.15CuO4 show
that a discontinuity in dispersion develops in the middle of the
highest energy LO phonon branch at low temperatures. The result suggests
dynamic short range unit cell doubling in the CuO2 plane along the
direction of the Cu-O bond, such as charge ordering on every other
row of oxygen. Such charge ordering is related to, but is different
from, the stripe charge ordering observed for nonsuperconducting
cuprates.
Nutzer