We have investigated the magnetic, thermodynamic, and electrical transport properties of EuAuSb single crystals as well as carrying out band structure calculations. The powder x-ray diffraction data confirm that EuAuSb crystallizes in ZrBeSi-type hexagonal structure with space group $P{6}_3/mmc$. The magnetic measurements reveal an antiferromagnetic (AFM) ordering in EuAuSb at ${\mathit{T}}_N=3.3$ K. This transition is further confirmed by heat capacity and electrical resistivity data. The isothermal magnetization data saturate at low magnetic field of ${\mu }_0{H}_s^c=2.9$ and ${\mu }_0{H}_s^{ab}=3.8$ T for $\mathit{H}\perp \mathit{c}$ and $\mathit{H}\parallel \mathit{c}$, respectively, while the magnetization along $\mathit{H}\perp \mathit{c}$ displays a metamagnetic transition around ${\mu }_0{H}_m^{ab}=0.95$ T. The electrical resistivity exhibits a metallic behavior down to 35 K; after that it shows an upturn until $T_N$ due to the influence of short-range interactions. The longitudinal and transverse magnetoresistances of EuAuSb are negative ($\sim -45\%$ and $-42\%$ in 10 T at 2 K, respectively); in the high field at $\mathit{T}\le 40$ K, they switch to a positive value above 40 K. Further, we observe a humplike anomaly in the Hall resistivity [${\rho }_{xy}\left(\mathit{H}\right)$] data below $T_N$, which is most likely a manifestation of the topological Hall effect. Our two-band model analysis of ${\rho }_{xy}\left(\mathit{H}\right)$ data indicates both hole and electron charge carriers contribute to the electrical transport of the compound. The electronic band structure calculations reveal a $\mathrm{\Gamma }$-centered nodal line in the absence of spin-orbit coupling (SOC). In the presence of SOC, the compound hosts the Dirac point. The $Z_2$ invariants, in the presence of effective time-reversal and inversion symmetries, categorize this system as a nontrivial topological material. Our combined experimental and theoretical studies suggest EuAuSb to be a potential AFM topological semimetal.

中文翻译：

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EuAuSb 的磁输运和电子结构：候选反铁磁狄拉克半金属

我们研究了 EuAuSb 单晶的磁性、热力学和电输运特性，并进行了能带结构计算。粉末X射线衍射数据证实EuAuSb结晶为具有空间群的ZrBeSi型六方结构$磷6_3/米米C$。磁性测量揭示了 EuAuSb 中的反铁磁 (AFM) 有序性${\mathit{时间}}_{氮}=3.3$ K. 热容量和电阻率数据进一步证实了这种转变。等温磁化数据在低磁场下饱和${\mu }_0{H}_s^C=2.9$和${\mu }_0{H}_s^{A乙}=3.8$ 为$\mathit{H}\perp \mathit{C}$和$\mathit{H}\parallel \mathit{C}$，而磁化强度沿$\mathit{H}\perp \mathit{C}$显示周围的变磁转变${\mu }_0{H}_{米}^{A乙}=0.95$ T. 电阻率低至 35 K 时表现出金属行为；之后它呈现出好转状态，直到${\mathrm{时间}}_{氮}$由于短程相互作用的影响。 EuAuSb 的纵向和横向磁阻均为负值（$～-45\%$和$-42\%$分别为 10 T、2 K）；在高场$\mathit{时间}\le 40$ K，它们在 40 K 以上切换到正值。此外，我们观察到霍尔电阻率出现驼峰状异常[${\rho }_{Xy}（\mathit{H}）$] 数据如下${\mathrm{时间}}_{氮}$，这很可能是拓扑霍尔效应的体现。我们的双频带模型分析${\rho }_{Xy}（\mathit{H}）$数据表明空穴和电子载流子都有助于化合物的电传输。电子能带结构计算揭示了$\mathrm{\gamma }$-在没有自旋轨道耦合（SOC）的情况下以中心节点线。在 SOC 存在的情况下，该化合物具有狄拉克点。这$Z_2$在存在有效的时间反转和反演对称性的情况下，不变量将该系统归类为非平凡的拓扑材料。我们的实验和理论相结合的研究表明，EuAuSb 是一种潜在的 AFM 拓扑半金属。