Enhanced charge density wave coherence in a light-quenched, high-temperature superconductor

Superconductivity and charge density waves (CDWs) are competitive, yet coexisting, orders in cuprate superconductors. To understand their microscopic interdependence, a probe capable of discerning their interaction on its natural length and time scale is necessary. We use ultrafast resonant soft x-ray scattering to track the transient evolution of CDW correlations in YBa2Cu3O6+x after the quench of superconductivity by an infrared laser pulse. We observe a nonthermal response of the CDW order characterized by a near doubling of the correlation length within ≈1 picosecond of the superconducting quench. Our results are consistent with a model in which the interaction between superconductivity and CDWs manifests inhomogeneously through disruption of spatial coherence, with superconductivity playing the dominant role in stabilizing CDW topological defects, such as discommensurations. Description Changing the balance of orders with light Charge-density wave (CDW) order, the spatial modulation of electronic density, is known to compete with superconductivity in copper oxide superconductors. This understanding comes largely from equilibrium experiments, and the dynamics of the interplay of these orders are less explored. Wandel et al. use ultrafast laser pulses to quickly quench superconductivity in samples of the YBa2Cu3O6+x superconductor, which temporarily enhanced the CDW order. The process increased the correlation length of the CDW order, suggesting that superconductivity stabilizes CDW defects that are removed by suppressing superconductivity. —JS Ultrafast resonant soft x-ray scattering is used to monitor the dynamics of the charge density wave order in YBa2Cu3O6+x.