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

TL;DR

This study demonstrates the successful doping of Tb into a topological insulator, inducing antiferromagnetic order and revealing surface state transport phenomena, thus advancing the understanding of magnetic topological phases.

Contribution

It reports the first observation of antiferromagnetic topological insulating state in Tb-doped BiSbTeS single crystals with detailed transport analysis.

Findings

Tb doping induces antiferromagnetic order below 10 K.

Surface states dominate transport below 150 K.

Strong 2D-like Shubnikov-de Haas oscillations observed.

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.