The origin of high-temperature superconductivity remains poorly understood to date. Over the past two decades, spatial oscillations of the electronic density known as charge-density waves (CDWs) have been found to coexist with high-temperature superconductivity in most prominent cuprate superconductors. The debate on whether CDWs help or hinder high-temperature superconductivity in cuprates is still ongoing. In principle, disorder at the atomic scale should strongly suppress both high-temperature superconductivity and CDWs. In this work, however, we ﬁnd that disorder created by irradiation increases the superconducting critical temperature by 50% while suppressing the CDW order, showing that CDWs strongly hinder bulk superconductivity. We show that this increase occurs because the CDWs could be frustrating the superconducting coupling between atomic planes.
Image: In an ideal system, orthogonal charge-spin stripes in adjacent layers prevent Josephson coupling between layers. Left: In the presence of disorder, distorted stripes around defects are not orthogonal, which reestablishes Josephson coupling between layers and increases TC.