Comment on ``Vortices with Fractional Flux in Two-Gap Superconductors and Extended Faddeev Model'', ``Phase Diagram of Planar U(1)xU(1) Superconductor'' and "Flux Noise in MgB2 Thin Films"

TL;DR

This paper critically examines recent claims about fractional vortices and BKT transitions in MgB2 thin films, arguing that the proposed phenomena are incompatible with MgB2's known electron-phonon interaction parameters.

Contribution

It provides a theoretical critique showing that the claimed fractional vortex BKT transition in MgB2 is inconsistent with its electron-phonon interaction parameters.

Findings

Recent claims of fractional vortex BKT transition in MgB2 are incompatible with its electron-phonon parameters.

Theoretical analysis challenges the feasibility of fractional vortices in MgB2.

The paper clarifies the limitations of current models regarding vortex behavior in MgB2.

Abstract

I show that recent theoretical [1,2] and experimental [3] claims about the possibility of the Berezinskii-Kosterlitz-Thouless (BKT) transition of ``fractional vortices'' in thin films of MgB2 are inconsistent with the parameters of the electron-phonon interaction in MgB2.