Fluctuating orders and quenched randomness in the cuprates

Abstract

We study a quasi-2D classical Landau-Ginzburg-Wilson effective field theory in the presence of quenched disorder in which incommensurate charge-density wave and superconducting orders are intertwined. The disorder precludes long-range charge-density wave order, but not superconducting or nematic order. We select three representative sets of input parameters and compute the corresponding charge-density wave structure factors using both large-N techniques and classical Monte Carlo simulations. Where nematicity and superconductivity coexist at low temperature, the peak height of the charge-density wave structure factor decreases monotonically as a function of increasing temperature, unlike what is seen in X-ray experiments on YBa2Cu3O6+x. Conversely, where the thermal evolution of the charge-density wave structure factor qualitatively agrees with experiments, the nematic correlation length, computed to one-loop order, is shorter than the charge-density wave correlation length.

Modification of structural disorder by hydrostatic pressure in the superconducting cuprate YBa2Cu3O6.73

“…On the other hand, the oxygen redistribution in the Cu-O layer under high-pressure suppresses the disorder-pinned CDW fluctuating portion. Therefore, we infer that a pressure condition causes to decrease the disorder strength (σ) 37,39,48 in the CuO 2 plane, which is reasonably proportional to or dominated by the quantity of the structural disorders in Cu-O chain layer. 36,49 Ultimately, the energy cost for developing the nematic order at the state-II (E II , i.e.…”

“…This circumstance may reduce the pinning centers for CDW fluctuation in the CuO 2 plane, 36 11 suppressing the disorder-pinned CDW fluctuation, which is consistent with the theoretical predictions. 33,37,38 As a consequence, we come to an answer to the initial question we posed. There are two factors contributing to the compression induced T c change.…”

“…In addition, our OO results support this behavior seems to be intrinsic. Since the fact that the modified structural disorder in the Cu-O layer (i.e., oxygen rearrangement) affects the charge distribution (i.e., charge-density potential) in the CuO 2 plane, the quenched disorder in the CuO 2 plane, which originates from the charge potential of defects, 37 is correspondingly modified through the pressure. This circumstance may reduce the pinning centers for CDW fluctuation in the CuO 2 plane, 36 11 suppressing the disorder-pinned CDW fluctuation, which is consistent with the theoretical predictions.…”

“…Theoretically, this nematic order also prefers structural nematicity (i.e., orthorhombicity). 37 By enhancing YBa 2 Cu 3 O 6+x 's orthorhombicity under hydrostatic-pressure, it would become easier to develop nematic order in compressed YBCO (state-II, labeled in Fig. 6(b)) compared to ambient pressure YBCO (state-I).…”

Vestigial nematicity from spin and/or charge order in the cuprates

“…46 An alternative way to view this is to consider the generalized version of this model in which both the CDW (which is an O(2) field) and the SDW (which is an O(2) × O(3) field) are generalized to O(N ) fields, and the problem can then be solved exactly in the N → ∞ limit. It has previously been shown by us 47 and others 48 that such an approach captures much of the physics of the actual physical problem. Our principal results concerning the nature of the interplay between CDW, SDW, and nematic order are summarized in the calculated phase diagrams in the figures below.…”