Absence of Broken Time-Reversal Symmetry in the Pseudogap State of the High Temperature La2-xSrxCuO4 Superconductor from Muon-Spin-Relaxation Measurements

We have performed zero-field muon-spin-relaxation measurements on single crystals of La(2-x)SrxCuO4 to search for spontaneous currents in the pseudogap 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 pseudogap. Comparison between experimental limits and the proposed circulating current states effectively eliminates the possibility that such states exist in this family of materials.