Charge Carrier Mediation and Ferromagnetism induced in MnBi6Te10 Magnetic Topological Insulators by antimony doping

TL;DR

This study demonstrates that antimony doping in MnBi6Te10 can induce a transition from antiferromagnetic to ferromagnetic ground state, adjusting charge carriers and potentially enabling high-temperature quantum anomalous Hall effects in magnetic topological insulators.

Contribution

It reveals that Sb substitution in MnBi6Te10 induces ferromagnetism and tunes charge carriers, advancing the development of magnetic topological insulators with high-temperature quantum effects.

Findings

Sb doping induces ferromagnetism in MnBi6Te10

Charge carrier type and concentration can be controlled by Sb substitution

A ferromagnetic topological insulator phase is achievable near x ~ 0.25

Abstract

A new kind of intrinsic magnetic topological insulators (MTI) MnBi2Te4 family have shed light on the observation of novel topological quantum effect such as quantum anomalous Hall effect (QAHE). However, the strong anti-ferromagnetic (AFM) coupling and high carrier concentration in the bulk hinder the practical applications. In closely related materials MnBi4Te7 and MnBi6Te10, the interlayer magnetic coupling is greatly suppressed by Bi2Te3 layer intercalation. However, AFM is still the ground state in these compounds. Here by magnetic and transport measurements, we demonstrate that Sb substitutional dopant plays a dual role in MnBi6Te10, which can not only adjust the charge carrier type and the concentration, but also induce the solid into a ferromagnetic (FM) ground state. AFM ground state region which is also close to the charge neutral point can be found in the phase diagram of Mn(SbxBi1-x)6Te10 when x ~ 0.25. An intrinsic FM-MTI candidate is thus demonstrated, and it may take a step further for the realization of high-quality and high-temperature QAHE and the related topological quantum effects in the future.