CHARGE ORDER AND ITS ROLE IN HIGH-TEMPERATURE CUPRATE SUPERCONDUCTIVITY
Abstract
Charge order has become one of the central topics in the physics of cuprate superconductors because it links the pseudogap regime, Fermi-surface reconstruction, and the competition between different electronic orders. During the last three decades, the concept evolved from early stripe correlations in La-based cuprates to a broader picture in which short-range and, in some cases, field-enhanced charge-density-wave correlations are observed in several hole-doped cuprate families. This brief review summarizes the main experimental evidence for charge order, discusses its relationship with superconductivity and the pseudogap, and outlines the present understanding of its role in high-temperature superconductivity. The comparison of neutron scattering, resonant x-ray scattering, scanning tunneling microscopy, NMR, and transport measurements shows that charge order is now widely regarded as a robust and nearly universal instability of underdoped cuprates. At the same time, available data indicate that charge order is not identical to the pseudogap and cannot by itself explain the mechanism of superconducting pairing. Instead, charge order should be viewed as an important component of an intertwined many-body state that strongly influences the electronic properties of cuprates.