Highly tunable topological system based on PbTe-SnTe binary alloy

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 Pb1-xSnxTe. 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.