Enhanced quasiparticle heat conduction of the multigap superconductor Lu2Fe3Si5

TL;DR

This study investigates the thermal conductivity of the multigap superconductor Lu2Fe3Si5, revealing enhanced quasiparticle heat conduction linked to electronic correlations from Fe 3d-electrons, with implications for understanding multigap superconductivity.

Contribution

It provides the first detailed thermal transport measurements of Lu2Fe3Si5, demonstrating its multigap nature and unusually high quasiparticle heat conduction compared to similar superconductors.

Findings

Multigap superconductivity confirmed by thermal conductivity data.

Enhanced quasiparticle heat conduction in the mixed state.

Electronic correlations from Fe 3d-electrons influence heat transport.

Abstract

The thermal transport measurements have been made on the Fe-based superconductor Lu2Fe3Si5 (Tc ~ 6 K) down to a very low temperature Tc/120. The field and temperature dependences of the thermal conductivity confirm the multigap superconductivity with fully opened gaps on the whole Fermi surfaces. In comparison to MgB2 as a typical example of the multigap superconductor in a p-electron system, Lu2Fe3Si5 reveals a remarkably enhanced quasiparticle heat conduction in the mixed state. The results can be interpreted as a consequence of the electronic correlations derived from Fe 3d-electrons.