Anomalous Dispersion of LO Phonons in <span class="aps-inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi mathvariant="normal">La</mi></mrow><mrow><mn>1.85</mn></mrow></msub></mrow><mrow><msub><mrow><mi mathvariant="normal">Sr</mi></mrow><mrow><mn>0.15</mn></mrow></msub></mrow><mrow><msub><mrow><mi mathvariant="normal">CuO</mi></mrow><mrow><mn>4</mn></mrow></msub></mrow></math></span> at Low Temperatures

R. J. McQueeney; Y. Petrov; T. Egami; M. Yethiraj; G. Shirane; Y. Endoh

doi:10.1103/PhysRevLett.82.628

Anomalous Dispersion of LO Phonons in ${La}_{1.85} {Sr}_{0.15} {CuO}_{4}$ at Low Temperatures

R. J. McQueeney, Y. Petrov, T. Egami, M. Yethiraj, G. Shirane, and Y. Endoh

Phys. Rev. Lett. 82, 628 – Published 18 January 1999

Abstract

Inelastic neutron scattering measurements of ${La}_{1.85} {Sr}_{0.15} {CuO}_{4}$ 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 ${CuO}_{2}$ 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.

Received 26 January 1998

DOI:https://doi.org/10.1103/PhysRevLett.82.628

Authors & Affiliations

R. J. McQueeney¹, Y. Petrov², T. Egami³, M. Yethiraj⁴, G. Shirane⁵, and Y. Endoh⁶

¹Los Alamos National Laboratory, Los Alamos, New Mexico 87545
²Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104
³Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104
⁴Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
⁵Brookhaven National Laboratory, Upton, New York 11973
⁶Department of Physics, Tohoku University, Sendai 980, Japan