Charge-Density-Wave and Superconductor Competition in Stripe Phases of High Temperature Superconductors

TL;DR

This paper investigates the competition and coexistence of superconducting and charge density wave orders in stripe phases of high-temperature superconductors, using effective models, RG analysis, and phase diagram exploration.

Contribution

It introduces an effective $O(4)$-symmetric nonlinear sigma model to analyze the competition and coexistence of SC and CDW orders in stripe phases, revealing a broad coexistence regime and detailed critical behavior.

Findings

Both orders can coexist over a broad parameter range.

The phase diagram features tetracritical points at finite temperatures.

Hedgehog topological excitations are RG irrelevant at the fixed point.

Abstract

We discuss the problem of competition between a superconducting (SC) ordered state with a charge density wave (CDW) state in stripe phases of high $T_c$ superconductors. We consider an effective model for each stripe motivated by studies of spin-gapped electronic ladder systems. We analyze the problem of dimensional crossover arising from inter-stripe SC and CDW couplings using non-Abelian bosonization and renormalization group (RG) arguments to derive an effective $O(4)$-symmetric nonlinear $\sigma$-model in $D=2+1$ for the case of when both inter-stripe couplings are of equal magnitude as well as equally RG relevant. By studying the effects of various symmetry lowering perturbations, we determine the structure of the phase diagram and show that, in general, it has a broad regime in which both orders coexist. The quantum and thermal critical behavior is discussed in detail, and the phase coexistence region is found to end at associated $T=0$ as well as $T>0$ tetracritical points. The possible role of hedgehog topological excitations of the theory is considered and argued to be RG irrelevant at the spatially anisotropic higher dimensional low-energy fixed point theory. Our results are also relevant to the case of competing N\'eel and valence bond solid (VBS) orders in quantum magnets on 2D isotropic square as well as rectangular lattices interacting via nearest neighbor Heisenberg exchange interactions.