We successfully grew single crystals of Si- and Ge-square-net compounds of NbSiSb and NbGeSb whose excellent crystalline quality are verified using single-crystal x-ray diffraction -2 scans, rocking curves, scanning and transmission electron microscopies. Since these two compounds share major crystallographic similarity with the topological nodal-line semimetals of ZrSiS family, we employ density functional theory (DFT) calculations and magnetotransport measurements to demonstrate their band structures as well as the electron scattering mechanisms. DFT calculations show that the fermiology shows strong anisotropy from the crystallographic c-axis to the ab-plane and weak anisotropy within the ab plane, which is consistent with the strong anisotropic magnetotransport behaviors. Following the Kohler's scaling rule we prove that similar interband and intraband electron-phonon scattering mechanisms work in both the NbSiSb and NbGeSb compounds. The study of electronic transport mechanism in the presence of external magnetic field renders deep insight into topological behavior together with it's Fermi surface, and the high similarity of crystallography and strong difference in band structures between the present single crystals and that of ZrSiS family provides the possibility to tune the band structure via element doping.

中文翻译：

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NbSiSb 和 NbGeSb 单晶方网化合物的磁输运性能


我们成功生长了 NbSiSb 和 NbGeSb 的 Si 和 Ge 方网化合物单晶，其优异的晶体质量通过单晶 X 射线衍射 -2 扫描、摇摆曲线、扫描和透射电子显微镜得到了验证。由于这两种化合物与 ZrSiS 族的拓扑节线半金属具有主要的晶体学相似性，因此我们采用密度泛函理论 (DFT) 计算和磁输运测量来证明它们的能带结构以及电子散射机制。 DFT计算表明，费米学表现出从晶体c轴到ab平面的强各向异性和ab平面内的弱各向异性，这与强各向异性磁输运行为一致。根据科勒比例规则，我们证明了类似的带间和带内电子声子散射机制在 NbSiSb 和 NbGeSb 化合物中都有效。外磁场下电子传输机制的研究可以深入了解拓扑行为及其费米面，并且现有单晶与ZrSiS族单晶在晶体学上的高度相似性和能带结构的巨大差异提供了可能性通过元素掺杂来调整能带结构。