Critical Doping for the Onset of Fermi-Surface Reconstruction by Charge-Density-Wave Order in the Cuprate Superconductor La_2-xSr_xCuO₄

The Seebeck coefficient S of the cuprate superconductor La2−xSrxCuO4 (LSCO) was measured in magnetic fields large enough to access the normal state at low temperatures, for a range of Sr concentrations from x ¼ 0.07 to x ¼ 0.15. For x ¼ 0.11, 0.12, 0.125, and 0.13, S=T decreases upon cooling to become negative at low temperatures. The same behavior is observed in the Hall coefficient RHðTÞ. In analogy with other hole-doped cuprates at similar hole concentrations p, the negative S and RH show that the Fermi surface of LSCO undergoes a reconstruction caused by the onset of charge-density-wave modulations. Such modulations have indeed been detected in LSCO by x-ray diffraction in precisely the same doping range. Our data show that in LSCO this Fermi-surface reconstruction is confined to 0.085 <p< 0.15. We argue that in the field-induced normal state of LSCO, charge-density-wave order ends at a critical doping pCDW ¼ 0.15 0.005, well below the pseudogap critical doping p⋆ ≃ 0.19.