Kosterlitz-Thouless signatures in the low-temperature phase of layered three-dimensional systems

TL;DR

This paper investigates layered three-dimensional systems with O(2) symmetry, revealing Kosterlitz-Thouless signatures in their low-temperature phase through a nonperturbative renormalization-group analysis, and proposes a generic phase diagram.

Contribution

It introduces a phase diagram for layered 3D systems with O(2) symmetry showing quasi-two-dimensional behavior and Kosterlitz-Thouless signatures using a nonperturbative RG approach.

Findings

Identification of a quasi-two-dimensional regime below the transition temperature.

Power-law variation of the order parameter with interplane coupling.

Signatures of Kosterlitz-Thouless physics in physical observables.

Abstract

We study the quasi-two-dimensional quantum O(2) model, a quantum generalization of the Lawrence-Doniach model, within the nonperturbative renormalization-group approach and propose a generic phase diagram for layered three-dimensional systems with an O(2)-symmetric order parameter. Below the transition temperature we identify a wide region of the phase diagram where the renormalization-group flow is quasi-two-dimensional for length scales smaller than a Josephson length $l_J$, leading to signatures of Kosterlitz-Thouless physics in the temperature dependence of physical observables. In particular the order parameter varies as a power law of the interplane coupling with an exponent which depends on the anomalous dimension (itself related to the stiffness) of the strictly two-dimensional low-temperature Kosterlitz-Thouless phase.