A Phenomenological Theory of Loop-Current Phases

TL;DR

This paper develops a phenomenological Ginzburg-Landau-Wilson theory to analyze the stability of loop-current and loop-spin-current phases, revealing their dependence on interaction strength and orbital susceptibility, especially in Dirac electron systems.

Contribution

It introduces a new theoretical framework to understand the stability conditions of loop-current phases using Landau theory and renormalization group analysis.

Findings

Loop-current and loop-spin-current phases are stable with strong enough interactions.

Large orbital susceptibility favors the stability of these phases.

Dirac electron systems are promising candidates for stable loop-current phases.

Abstract

A phenomenological theory of the loop-current and loop-spin-current phases is proposed. In order to investigate the stability of these phases, a Ginzburg-Landau-Wilson type action is constructed as a functional of the orbital magnetization. From the analysis of this action based on the Landau theory and momentum-shell one-loop renormalization group theory, it is found that the loop-current and loop-spin-current phases are stable if a certain interaction between the orbital magnetizations is sufficiently large. Moreover, these phases are likely to be stable in systems with large orbital susceptibility, for example, Dirac electron systems.