Two-band superconductivity featuring different anisotropies in the ternary iron silicide Lu$_{2}$Fe$_{3}$Si$_{5}$

TL;DR

This study investigates the two-gap superconductivity in Lu$_{2}$Fe$_{3}$Si$_{5}$, revealing that its two electronic bands exhibit distinct anisotropies, which are crucial for understanding its superconducting properties.

Contribution

The paper provides detailed experimental evidence of different anisotropies in the two bands of Lu$_{2}$Fe$_{3}$Si$_{5}$, highlighting the interplay between them in two-gap superconductivity.

Findings

Active band is quasi-one-dimensional.

Passive band has nearly isotropic virtual $H_{c2}$.

Two bands exhibit different anisotropies similar to MgB$_{2}$.

Abstract

We report detailed studies of the upper critical field and low-temperature specific heat in the two-gap superconductor Lu$_{2}$Fe$_{3}$Si$_{5}$. The anisotropy of the upper critical field suggests that the active band is quasi-one-dimensional. Low-temperature specific heat in magnetic fields reveals that the virtual $H_{c2}$ in the passive band is almost isotropic. These results strongly indicate that the two bands have two different anisotropies, similar to the typical two-gap superconductor MgB$_{2}$, and their interplay may be essential to the two-gap superconductivity in Lu$_{2}$Fe$_{3}$Si$_{5}$.