Topological semimetals have been attracting great interest for their superb potentials. While many theoretical and experimental investigations have been performed for topological semimetals, their materials platform is still in demand. Here, we report a highly tunable materials system for topological semimetal, indium (In)-doped $\mathrm{P}{\mathrm{b}}_{1-x}\mathrm{S}{\mathrm{n}}_x\mathrm{Te}$. By exploring the crystals with varying Pb/Sn ratios and In doping levels, a phase formation with low carrier concentration, high mobility, and large anomalous Hall effect is found for a finite area of the composition between topological crystalline insulator and normal insulator at ambient pressure. Furthermore, the in-plane anomalous Hall effect as a hallmark of Berry-curvature generation is also observed at low temperatures, where optical second-harmonic generation reveals the breaking of inversion symmetry. These results show that there is a finite range of topological semimetal phase in the PbTe-SnTe binary alloy, providing a promising materials platform to investigate the versatile nature of topological semimetals.

中文翻译：

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基于PbTe-SnTe二元合金的高度可调拓扑系统

拓扑半金属以其极好的潜力而引起了极大的兴趣。尽管已对拓扑半金属进行了许多理论和实验研究，但仍需要其材料平台。在这里，我们报告了一种用于铟（In）掺杂的拓扑半金属的高度可调的材料系统$\mathrm{P}{\mathrm{b}}_{\mathrm{1个}-X}\mathrm{小号}{\mathrm{ñ}}_X特$。通过探索具有变化的Pb / Sn比和In掺杂水平的晶体，在环境压力下，对于有限的拓扑晶体绝缘体和正常绝缘体之间的有限组成区域，发现了低载流子浓度，高迁移率和大异常霍尔效应的相形成。 。此外，在低温下还观察到了平面异常霍尔效应作为贝里曲率产生的标志，光学二次谐波产生揭示了反对称性的破坏。这些结果表明，PbTe-SnTe二元合金中存在有限范围的拓扑半金属相，为研究拓扑半金属的通用性提供了有希望的材料平台。