# X-ray Dichroism and the Pseudogap Phase of Cuprates

## TL;DR

This paper critically examines x-ray dichroism experiments in cuprates, questioning the evidence for broken parity symmetry in the pseudogap phase and proposing further experiments to clarify the origin of observed signals.

## Contribution

The study challenges previous interpretations of x-ray dichroism as evidence of parity breaking in cuprates and suggests alternative explanations and experimental tests.

## Key findings

- Parity-breaking signal unlikely based on crystal structures
- Alternative origins for the dichroism signal are plausible
- Proposes specific x-ray scattering experiments for validation

## Abstract

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.