Linear Magnetoresistance and Type-I Superconductivity in $\beta$-IrSn$_4$

TL;DR

This study reveals that $eta$-IrSn$_4$ exhibits unusual linear magnetoresistance and type-I superconductivity, linked to its Dirac-like electronic structure and high Fermi velocity, challenging existing models and suggesting topological properties.

Contribution

It provides the first detailed investigation of $eta$-IrSn$_4$'s electronic properties, highlighting its unconventional linear magnetoresistance and type-I superconductivity linked to Dirac points.

Findings

Linear magnetoresistance cannot be explained by existing models.

Superconducting transition shows a significant specific-heat jump in magnetic fields.

High Fermi velocity of linearly dispersive multibands influences superconductivity.

Abstract

Layered material $\beta$-IrSn$_4$ ($I4_1/acd$, $D^{20}_{4h}$, #142), whose electron bands have symmetry-enforced Dirac points, was investigated using high-quality single crystals. It exhibits a pronounced linear field-dependence of magnetoresistance (LMR), which cannot be explained by currently existing models. Structures in the field-angle dependence of magnetoresistance and Hall resistivity are attributable to the Fermi surface topology; the presence of open orbits is inferred. At the superconducting (SC) transition, the specific-heat jump exhibits a significant increase in applied fields, revealing the type-I SC nature. This feature is attributable to the high Fermi velocity of linearly dispersive multibands. To clarify the mechanism of the puzzling LMR, investigations into the topological nature of those multibands in applied fields are highly desired.