Correlated insulator in two Coulomb-coupled quantum wires

TL;DR

This paper investigates how two Coulomb-coupled quantum wires can exhibit an incompressible insulating phase similar to phenomena observed in bilayer graphene, using bosonization to analyze phase behavior and finite-temperature responses.

Contribution

It demonstrates the emergence of an insulating phase in coupled quantum wires due to strong interactions, paralleling experimental observations in bilayer graphene.

Findings

Incompressible insulating phase arises in lightly doped electron-hole wires.

Phase characterized by a parity-even charge density wave without interwire coherence.

Finite-temperature behavior aligns with exciton solid phenomenology.

Abstract

Motivated by the recently discovered incompressible insulating phase in the bilayer graphene exciton experiment [arXiv:2306.16995], we study using bosonization two Coulomb-coupled spinless quantum wires and examine the possibility of realizing the similar phenomenology in one dimension. We explore the possible phases as functions of $k_{F}$'s and interactions. We show that an incompressible insulating phase can arise for two lightly doped electron-hole quantum wires (i.e., $k_{F1}=-k_{F2}$ and small $|k_{F1}|$) due to strong interwire interactions. Such an insulating phase forms a parity-even wire-antisymmetric charge density wave without interwire phase coherence, which melts to a phase allowing for a perfect negative drag upon heating. The finite-temperature response is qualitatively consistent with the ``exciton solid'' phenomenology in the bilayer graphene exciton experiment.