Stability of the smectic phase in arrays of parallel quantum wires

TL;DR

This paper investigates the stability of the smectic phase in arrays of parallel quantum wires derived from Dirac fermions, revealing a phase diagram with stable smectic metal and Fermi liquid phases influenced by Coulomb interactions.

Contribution

It presents a microscopic model showing that only smectic metal and Fermi liquid phases occur, with the smectic phase stable in the ideal limit and a critical Coulomb coupling separating phases.

Findings

Smectic metal phase is stable at zero transverse wavefunction spread.

Finite spread introduces a critical Coulomb coupling for phase transition.

Superconductivity is absent in the considered microscopic model.

Abstract

Using bosonization, we study a microscopic model of parallel quantum wires constructed from two dimensional Dirac fermions in the presence of periodic topological domain walls. The model accounts for the lateral spread of the wavefunctions $\ell$ in the transverse direction to the wires. The gapless modes confined to each domain wall are shown to form Luttinger liquids, which realize a well known smectic non-Fermi liquid fixed point when interwire Coulomb interactions are taken into account. Perturbative studies on phenomenological models have shown that the smectic fixed point is unstable towards a variety of phases such as superconductivity, stripe, smectic and Fermi liquid phases. Here, we show that the considered microscopic model leads to a phase diagram with only smectic metal and Fermi liquid phases. The smectic metal phase is stable in the ideal quantum wire limit $\ell\to0$. For finite $\ell$, we find a critical Coulomb coupling $\alpha_{c}$ separating the strong coupling smectic metal from a weak coupling Fermi liquid phase. We conjecture that the absence of superconductivity should be a generic feature of similar microscopic models. Finally, we discuss the physical realization of this model with moire heterostructures.