Angle Resolved Photemission Experiments to look for Time-reversal Violation in Cuprates

Abstract

The recent experiments reported by Borisenko et al. (cond-mat/0305179 v2), are examined in light of the conditions to be satisfied in the search for time-reversal violation by circularly polarized ARPES. Two principal problems are found: (1) A lack of any evidence for the magnitude of the pseudogap or the temperature of its onset in the samples studied. (2) A difference in the dichroic signal at low and high temperatures. The difference is greater than the stated error bars and is contrary to the conclusions reached in the paper.