Antiferromagnetic topological insulating state in Tb${}_{0.02}$Bi${}_{1.08}$Sb${}_{0.9}$Te${}_2$S single crystals

Abstract

Topological insulators are emerging materials with insulating bulk and symmetry protected nontrivial surface states. One of the most fascinating transport behaviors in a topological insulator is the quantized anomalous Hall insulator, which has been observed inmagnetic-topological-insulator-based devices. In this work, we report a successful doping of rare earth element Tb into Bi${}_{1.08}$Sb${}_{0.9}$Te${}_2$S topological insulator single crystals, in which the Tb moments are antiferromagnetically ordered below ~10 K. Benefiting from the in-bulk-gap Fermi level, transport behavior dominant by the topological surface states is observed below ~ 150 K. At low temperatures, strong Shubnikov-de Haas oscillations are observed, which exhibit 2D-like behavior. The topological insulator with long range magnetic ordering in rare earth doped Bi${}_{1.08}$Sb${}_{0.9}$Te${}_2$S single crystal provides an ideal platform for quantum transport studies and potential applications.

15 pages, 3 figures