A recent polarized x-ray absorption experiment on the high temperature cuprate superconductor Bi2Sr2CaCu2O8 indicates the presence of broken parity symmetry below the temperature, T*, where a pseudogap appears in photoemission. We critically analyze the x-ray data, and conclude that a parity-breaking signal of the kind suggested is unlikely based on the crystal structures reported in the literature. Possible other origins of the observed dichroism signal are discussed. We propose x-ray scattering experiments that can be done in order to determine whether such alternative interpretations are valid or not.
@article{arxiv.0704.0599,
title = {X-ray Dichroism and the Pseudogap Phase of Cuprates},
author = {S. Di Matteo and M. R. Norman},
journal= {arXiv preprint arXiv:0704.0599},
year = {2009}
}
Comments
final version to be published in Phys Rev B: some calculational details added, clarification of XNLD contamination and biaxiality, more discussion on possible space groups and previous optics results