Thermopower across the phase diagram of the cuprate La1.6−xNd0.4SrxCuO4: Signatures of the pseudogap and charge density wave phases

The Seebeck coefficient (thermopower) S of the cuprate superconductor La1.6−xNd0.4SrxCuO4 was measured across its doping phase diagram (from p=0.12 to p=0.25), at various temperatures down to T≃2 K, in the normal state accessed by suppressing superconductivity with a magnetic field up to H=37.5 T. The magnitude of S/T in the T=0 limit is found to suddenly increase, by a factor ≃5, when the doping is reduced below p★=0.23, the critical doping …