Magnetoresistance and Kondo effect in the nodal-line semimetal VAs$_2$

TL;DR

This study combines calculations and experiments to explore the electronic properties of VAs₂, revealing its nodal-line semimetal nature, magnetic impurity effects, and large magnetoresistance, highlighting the role of V in topological materials.

Contribution

It provides the first detailed analysis of VAs₂'s electronic structure, magnetic impurities, and magnetoresistance, linking these features to its topological properties and charge-carrier compensation.

Findings

VAs₂ is a nodal-line semimetal without spin-orbit coupling.

Magnetic impurity V^{4+} causes a resistivity minimum at 11 K.

Large positive magnetoresistance of 649% at 10 K and 9 T.

Abstract

We performed calculations of the electronic band structure and the Fermi surface as well as measured the longitudinal resistivity $\rho_{xx}(T,H)$, Hall resistivity $\rho_{xy}(T,H)$, and magnetic susceptibility as a function of temperature and various magnetic fields for VAs$_2$ with a monoclinic crystal structure. The band structure calculations show that VAs$_2$ is a nodal-line semimetal when spin-orbit coupling is ignored. The emergence of a minimum at around 11 K in $\rho_{xx}(T)$ measured at $H$ = 0 demonstrates that an additional magnetic impurity (V$^{4+}$, $S$ = 1/2) occurs in VAs$_2$ single crystals, evidenced by both the fitting of $\rho_{xx}(T)$ data and the susceptibility measurements. It was found that a large positive magnetoresistance (MR) reaching 649\% at 10 K and 9 T, its nearly quadratic field dependence, and a field-induced up-turn behavior of $\rho_{xx}(T)$ emerge also in VAs$_2$, although MR is not so large due to the existence of additional scattering compared with other topological nontrival/trival semimetals. The observed properties are attributed to a perfect charge-carrier compensation, which is evidenced by both calculations relying on the Fermi surface and the Hall resistivity measurements. These results indicate that the compounds containing V ($3d^3 4s^2$) element as a platform for studying the influence of magnetic impurities to the topological properties.