Striped superconductors: How the cuprates intertwine spin, charge and superconducting orders

Understand

Recent transport experiments in the original cuprate high temperature superconductor, {La$_{2-x}$Ba$_x$CuO$_4$}, have revealed a remarkable sequence of transitions and crossovers which give rise to a form of dynamical dimensional reduction, in which a bulk crystal becomes essentially superconducting in two directions while it remains poorly metallic in the third.

• We identify these phenomena as arising from a distinct new superconducting state, the "striped superconductor," in which the superconducting order is spatially modulated, so that its volume average value is zero.
• Here, in addition to outlining the salient experimental findings, we sketch the order parameter theory of the state, stressing some of the ways in which a striped superconductor differs fundamentally from an ordinary (uniform) superconductor, especially concerning its response to quenched randomness.
• We also present the results of DMRG calculations on a model of interacting electrons in which sign oscillations of the superconducting order are established.