Uniaxial pressure control of competing orders in a high-temperature superconductor

Squeezing into the third dimension Cuprate superconductors are known to harbor charge order in part of their phase diagram. Curiously, the order has a two-dimensional (2D) character at zero magnetic field, whereas a 3D order appears at high fields. Kim et al. now show that in a yttrium-based cuprate, a 3D charge order can be induced even at zero magnetic field. The authors compressed the material along one direction and measured a large inelastic x-ray scattering signal that was consistent with the formation of a 3D order. The measurements suggest that the induced order is associated with an optical lattice mode in the material. Science , this issue p. 1040