Charge-Density-Wave Order and Pseudogap in Bi₂Sr_2-x La_x CuO_6+δ

Abstract

High temperature superconductivity appears in the cuprates when a spin order is destroyed, while the role of charge is less known. In this review, we describe our recent ⁶³Cu-nuclear magnetic resonance study that discovered a long-range charge density wave (CDW) order in Bi₂Sr_2-x La_x CuO_6+δ , setting in above the superconducting dome, under an in-plane field H_||>10 T. The doping dependence of the onset temperature T_CDW scales with the pseudogap temperature T *, which suggests that the T * is a high-temperature fingerprint of the CDW. The T_CDW smoothly takes over the spin order temperature T_N beyond a critical doping level at which superconductivity starts to emerge. These results provide new insights into the relationship between spin order, CDW and the pseudogap, and their connections to high-temperature superconductivity.