Multiple broken symmetries in striped La2−xBaxCuO4 detected by the field-symmetric Nernst effect

Abstract

We report a thermoelectric investigation of the stripe and superconducting phases of the cuprate La2−xBaxuO4 near x=1/8. We vary the doping and the magnetic field to identify features in the field-symmetric Nernst effect consistent with the reports of time-reversal symmetry breaking above the superconducting Tc. Crucially, we further detect a field-invariant peak at the stripe charge order temperature, TCO. Our observations suggest the onset of a nontrivial charge ordered phase at TCO, and the subsequent presence of spontaneously generated vortices before the emergence of bulk superconductivity.