Magnetic and transport properties in magnetic topological insulators MnBi2Te4(Bi2Te3)n (n=1,2)

TL;DR

This study investigates the magnetic and transport properties of MnBi2Te4(Bi2Te3)n (n=1,2) crystals, revealing suppressed antiferromagnetic coupling and ferromagnetic behavior at low temperatures, which are promising for quantum anomalous Hall effects.

Contribution

It demonstrates how increasing Bi2Te3 layers suppresses antiferromagnetic coupling and induces ferromagnetism, offering new platforms for topological phase exploration.

Findings

Weak antiferromagnetic transitions at 12.3 K and 10.5 K

Observation of ferromagnetic hysteresis at low temperatures

Potential for realizing quantum anomalous Hall effect without external magnetic field

Abstract

The observation of quantized anomalous Hall conductance in the forced ferromagnetic state of MnBi2Te4 thin flakes has attracted much attentions. However, strong magnetic field is needed to fully polarize the magnetic moments due to the large antiferromagnetic interlayer exchange coupling. Here, we reported the magnetic and electrical transport properties of the magnetic van der Waals MnBi2Te4(Bi2Te3)n (n=1,2) single crystals, in which the interlayer antiferromagnetic exchange coupling is greatly suppressed with the increase of the separation layers Bi2Te3. MnBi4Te7 and MnBi6Te10 show weak antiferromagnetic transition at 12.3 and 10.5 K, respectively. The ferromagnetic hysteresis was observed at low temperature for both of the crystals, which is quite crucial for realizing the quantum anomalous Hall effect without external magnetic field. Our work indicates that MnBi2Te4(Bi2Te3)n (n=1,2) provide ideal platforms to investigate the rich topological phases with going to their 2D limits.