Linear magnetoresistance, anomalous Hall effect and de Haas-van Alphen oscillations in antiferromagnetic SmAg${}_2$Ge${}_2$ single crystals

Abstract

Understanding the interplay among magnetism, electron correlations, and complex electronic structures in rare-earth materials requires both high-quality single crystals and systematic investigation of their electronic properties. In this study, we have successfully grown a single crystal of SmAg${}_2$Ge${}_2$ and investigated its anisotropic physical properties and de Haas-van Alphen (dHvA) quantum oscillations through experimental and theoretical approaches. SmAg${}_2$Ge${}_2$ crystallizes in the well known ThCr${}_2$Si${}_2$-type tetragonal structure with lattice parameters, $a=4.226$~à ~ and $c=11.051$~à . Electrical transport and magnetization measurements indicate that it is metallic and exhibit antiferromagnetic ordering below the Néel temperature, $T_{\mathrm{N}}$ = 9.2~K. SmAg${}_2$Ge${}_2$ exhibits a linear non-saturating magnetoresistance, reaching $\sim 97$\% at $2$~K for applied magnetic field $B$~$\parallel [001]$ and a significant anomalous Hall effect with an anomalous Hall angle of $0.10-0.14$. Additionally, magnetization measurements reveal dHvA quantum oscillations for magnetic fields greater than $8$~T. Our calculated electronic structure, quantum oscillations, and anomalous Hall effect in the canted antiferromagnetic state closely align with experimental results, underscoring the role of complex electronic structure and spin-canting-driven non-zero Berry curvature in elucidating the physical properties of SmAg${}_2$Ge${}_2$