Critical Doping for the Onset of Fermi-Surface Reconstruction by Charge-Density-Wave Order in the Cuprate Superconductor La${}_{2-x}$Sr${}_x$CuO${}_4$

Abstract

The Seebeck coefficient $S$ of the cuprate superconductor La${}_{2-x}$Sr${}_x$CuO${}_4$ (LSCO) was measured in magnetic fields large enough to access the normal state at low temperatures, for a range of Sr concentrations from $x=0.07$ to $x=0.15$. For $x=0.11$, 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 $R_H(T)$. In analogy with other hole-doped cuprates at similar hole concentrations $p$, the negative $S$ and $R_H$ 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 $p_{\mathrm{CDW}}=0.15\pm 0.005$, well below the pseudogap critical doping $p^{\star }\simeq 0.19$.