Putative non-trivial topology in YNiSn$_{2}$ Dirac semimetal

TL;DR

This study reveals that YNiSn₂ exhibits giant positive magnetoresistance, field-induced metal-insulator crossover, and two-dimensional electronic features, suggesting non-trivial topological properties in this Dirac semimetal candidate.

Contribution

The paper provides evidence of putative non-trivial topology in YNiSn₂ through comprehensive experimental characterization and quantum oscillation analysis.

Findings

Giant positive magnetoresistance of nearly 1000% at 1.8 K

Field-induced metal-insulator-like crossover above 3 T

Anisotropic quantum oscillations indicating 2D electronic bands

Abstract

In this work, we investigate the properties of single-crystalline YNiSn$_{2}$ through x-ray powder diffraction, elemental analysis, electrical resistivity, magnetic susceptibility, and specific heat measurements. YNiSn$_{2}$ crystallizes in an orthorhombic structure within the Cmcm space group (63), forming plate-like crystals with the $b$ axis oriented out of the plane. The compound exhibits weak Pauli paramagnetism with a susceptibility of $\chi_{0} = 2(3) \times 10^{-5}$ emu/mol-Oe and a small Sommerfeld coefficient of $\gamma = 4$ mJ/mol$\cdot$K$^{2}$, indicating a low density of states at the Fermi level. Notably, at 1.8 K, YNiSn$_{2}$ displays a giant positive magnetoresistance of nearly 1000\%, which increases quasi-linearly with the magnetic field up to $B = 16$ T, alongside a field-induced metal-insulator-like crossover under applied magnetic fields $>$ 3 T. Furthermore, highly anisotropic dHvA quantum oscillations suggest a two-dimensional electronic band character from which a low effective mass and a high Fermi velocity could be extracted.