Antiferromagnetic Topological Insulator MnBi2Te4: Synthesis and Magnetic properties

TL;DR

This paper reports the successful synthesis and characterization of MnBi2Te4, the first intrinsic antiferromagnetic topological insulator, highlighting its magnetic properties, structure, and potential for future quantum phenomena research.

Contribution

It presents the first synthesis and detailed analysis of high-quality MnBi2Te4 single crystals as an intrinsic AFM topological insulator, advancing understanding of its magnetic and structural properties.

Findings

MnBi2Te4 exhibits A-type antiferromagnetic order below 25 K.

The crystal structure is a septuple layer van der Waals layered system.

Surface oxidation poses challenges for future thin-layer studies.

Abstract

Recently, MnBi2Te4 has been discovered as the first intrinsic antiferromagnetic topological insulator (AFM TI), and will become a promising material to discover exotic topological quantum phenomena. In this work, we have realized the successful synthesis of high-quality MnBi2Te4 single crystals by solid-state reactions. The as-grown MnBi2Te4 single crystal exhibits a van der Waals layered structure, which is composed of septuple Te-Bi-Te-Mn-Te-Bi-Te sequences as determined by powder X-ray diffraction (PXRD) and high-resolution high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM). The magnetic order below 25 K as a consequence of A-type antiferromagnetic interaction between Mn layers in the MnBi2Te4 crystal suggests the unique interplay between antiferromagnetism and topological quantum states. The transport measurements of MnBi2Te4 single crystals further confirm its magnetic transition. Moreover, the unstable surface of MnBi2Te4, which is found to be easily oxidized in air, deserves attention for onging research on few-layer samples. This study on the first AFM TI of MnBi2Te4 will guide the future research on other potential candidates in the MBixTey family (M = Ni, V, Ti, etc.).