Site mixing induced ferrimagnetism and anomalous transport properties of the Weyl semimetal candidate MnSb2Te4

Abstract

$\mathrm{Mn}{\mathrm{Sb}}_2{\mathrm{Te}}_4$ has been proposed to have magnetic topological states as a potential Weyl semimetal. We synthesized single crystals of $\mathrm{Mn}{\mathrm{Sb}}_2{\mathrm{Te}}_4$ and systematically investigated their structural and physical properties. $\mathrm{Mn}{\mathrm{Sb}}_2{\mathrm{Te}}_4$ has an isostructural septuple-layered structure that is similar to the magnetic topological insulator $\mathrm{Mn}{\mathrm{Bi}}_2{\mathrm{Te}}_4$ but possesses transpositional Mn and Sb atoms between the sublayers. Magnetic and specific-heat measurements revealed a ferrimagnetic phase transition with a Curie temperature $T_{\mathrm{C}}$ of ∼31 K in $\mathrm{Mn}{\mathrm{Sb}}_2{\mathrm{Te}}_4$, which originates from the interaction of the interexchanged ${\mathrm{Mn}}^{2+}$ ions. As the temperature decreases below $T_{\mathrm{C}}$, negative longitudinal magnetoresistance and anomalous Hall effect are observed, implying a non-negligible connection between the magnetism and expected transport carriers that may be driven by topological bands. Our results indicate that ferrimagnetic $\mathrm{Mn}{\mathrm{Sb}}_2{\mathrm{Te}}_4$ provides insights for further studies on magnetic topological materials.