paper

Evidence of a Hybridized Topological State in Weyl Semimetal/Topological Insulator Mn $_{3 + x}$ Sn $_{1 - x}$ /Bi $_{0.85}$ Sb $_{0.15}$ Heterostructures

arXiv:2605.23765

Abstract

We report magnetotransport evidence of a hybridized Weyl semimetal (WSM) Fermi arc/topological insulator (TI) surface state at the interface of a ferromagnetic Mn $_{3 + x}$ Sn $_{1 - x}$ /Bi $_{0.85}$ Sb $_{0.15}$ heterostructure. High target utilization sputtering (HiTUS) was used to grow polycrystalline Mn $_{3 + x}$ Sn $_{1 - x}$ films and Mn $_{3 + x}$ Sn $_{1 - x}$ /Bi $_{0.85}$ Sb $_{0.15}$ heterostructures on thermally oxidized Si/SiO $_{2}$ (100) substrates that exhibit the negative coefficient anomalous Hall effect (AHE) resulting from topological Weyl node transport. When various defects and impurities are introduced into these Mn $_{3 + x}$ Sn $_{1 - x}$ films, a ferromagnetic (FM) phase develops that practically eliminates the topological Weyl node conduction. These FM Mn $_{3 + x}$ Sn $_{1 - x}$ films exhibit large exchange bias effects below T=200 K that we attribute to the coexistence of a FM phase and the triangular antiferromagnetic (AFM) WSM phase. When Bi $_{0.85}$ Sb $_{0.15}$ overlayers are grown on the FM Mn $_{3 + x}$ Sn $_{1 - x}$ , the magnetotransport signal of Weyl node topological transport is restored, an effect we do not observe when replacing the Bi $_{0.85}$ Sb $_{0.15}$ TI with heavy metal overlayers. We attribute the restoration of the Weyl node topological transport to the formation of a hybridized topological state at the WSM/TI interface.

Evidence of a Hybridized Topological State in Weyl Semimetal/Topological Insulator Mn3+x​Sn1−x​/Bi0.85​Sb0.15​ Heterostructures

Abstract

Evidence of a Hybridized Topological State in Weyl Semimetal/Topological Insulator Mn $_{3 + x}$ Sn $_{1 - x}$ /Bi $_{0.85}$ Sb $_{0.15}$ Heterostructures