Hole doping and antiferromagnetic correlations above the Néel temperature of the topological semimetal (Sr1−xKx)MnSb2

Abstract

Neutron diffraction and magnetic susceptibility studies of orthorhombic single crystal (Sr0.97K0.03)MnSb2 confirm the three dimensional (3D) C-type antiferromagnetic (AFM) ordering of the Mn 2+ moments at TN = 305 ± 3 K which is slightly higher than that of the parent SrMnSb2 with TN = 297 ± 3 K. Susceptibility measurements of the K-doped and parent crystals above TN 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 TN to at least ∼ 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.

Controlling magnetic order, magnetic anisotropy, and band topology in the semimetalsSr(Mn0.9Cu0.1)Sb2andIslam1, Choudhary2, Liu3 et al. 2020Phys. Rev. BSelf Cite

“…This is typical of quasi -two-dimensional (2D) AFM systems for which strong 2D correlations develop at a much higher temperature than that of the 3D transition temperature. Indeed, in SrMnSb 2 , 2D AFM correlations are observed up to 560 K [11].…”

“…Corrected magnetization versus the inverse applied magnetic field (1/H ) perpendicular to MnSb planes, M(1/H ), of Sr(Mn 0.9 Zn 0.1 )Sb 2 at various as indicated, showing dHvA oscillations (data were corrected for an FM contribution as discussed in Refs. [10,11]). (b) Numerical FT spectra obtained from the M(1/H ) data shown in (a).…”

“…(c) Temperature dependence of the integrated intensity (from 40 to 120 T) of the FT spectra shown in (b). (d) Comparison of FT spectra at T = 2 K of the parent compound SrMnSb 2 , and the doped compounds Sr(Mn 0.9 Zn 0.1 )Sb 2 and (Sr 0.97 K 0.03 )MnSb 2 [11]. applied field.…”

“…Figure 3(a) shows the magnetization of Sr(Mn 0.9 Zn 0.1 )Sb 2 (for H ⊥ ), after removing a ferromagnetic impurity component (as described in more detail in Refs. [10,11]) versus the inverse of the applied field M(1/H ) at various temperatures. Direct numerical Fourier transforms (FT) of M(1/H ) yield the FT spectra shown in Fig.…”

“…De Haas van Alphen (dHvA) oscillations can provide a sensitive probe of the Fermi surface geometry and are extensively used to characterize topological semimetals. In (Sr 0.97 K 0.03 )MnSb 2 , magnetization versus applied magnetic field exhibits dHvA oscillations with a slight frequency shift as compared to the parent compound, presumably due to hole doping of the system [11]. Here, we examine the effect of Cu and Zn substitutions of the Mn site-i.e., Sr(Mn 0.9 Cu 0.1 )Sb 2 and Sr(Mn 0.9 Zn 0.1 )Sb 2 -by employing single-crystal neutron diffraction techniques and magnetic measurements.…”