Absence of broken time-reversal symmetry in the pseudogap state of the high temperature LaSrCuO superconductor from muon-spin-relaxation measurements

MacDougall, G. J.*; Aczel, A. A.*; Carlo, J. P.*; Ito, Toshimitsu*; Rodriguez, J.*; Russo, P. L.*; Uemura, Yasutomo*; Wakimoto, Shuichi; Luke, G. M.*

Physical Review Letters, 101(1), p.017001_1 - 017001_4, 2008/07

https://doi.org/10.1103/PhysRevLett.101.017001

We have performed zero-field muon spin rotation measurements on single crystals of LaSrCuO to search for spontaneous currents in the pseudo-gap state. By comparing measurements on materials across the phase diagram, we put strict upper limits on any possible time-reversal symmetry breaking fields that could be associated with the pseudo-gap. Comparison between experimental limits and proposed circulating current states effectively eliminates the possibility that such states exist in this family of materials.