Hole Doping and Antiferromagnetic Correlations above the N{é}el temperature of the Topological Semimetal (Sr${}_{1-x}$K${}_x$)MnSb${}_2$

Abstract

Neutron diffraction and magnetic susceptibility studies of orthorhombic single crystal {\Ksub} confirm the three dimensional (3D) C-type antiferromagnetic (AFM) ordering of the Mn${}^{2+}$ moments at $T_{\mathrm{N}}=305\pm 3$ K which is slightly higher than that of the parent SrMnSb${}_2$ with $T_{\mathrm{N}}=297\pm 3$ K. Susceptibility measurements of the K-doped and parent crystals above $T_{\mathrm{N}}$ are characteristic of 2D AFM systems. This is consistent with high temperature neutron diffraction of the parent compound that display persisting 2D AFM correlations well above $T_{\mathrm{N}}$ to at least $\sim 560$ K with no evidence of a ferromagnetic phase. Analysis of the de Haas van Alphen magnetic oscillations of the K-doped crystal is consistent with hole doping.