Atomic-Layer-Controlled Magnetic Orders in MnBi2Te4-Bi2Te3 Topological Heterostructures

TL;DR

This study demonstrates atomic-layer control of magnetic orders in MnBi2Te4-Bi2Te3 heterostructures, revealing how ferromagnetic and antiferromagnetic states can be selectively manipulated by structural parameters.

Contribution

It introduces a method to control magnetic orders in topological heterostructures through atomic-layer engineering, providing new insights into magnetism in topological materials.

Findings

AFM order is determined by Mn-Mn distance.

FM order depends on Bi2Te3/MnBi2Te4 ratio.

Magnetic orders can be independently tuned.

Abstract

The natural van der Waals superlattice MnBi2Te4-(Bi2Te3)m provides an optimal platform to combine topology and magnetism in one system with minimal structural disorder. Here, we show that this system can harbor both ferromagnetic (FM) and antiferromagnetic (AFM) orders and that these magnetic orders can be controlled in two different ways by either varying the Mn-Mn distance while keeping the Bi2Te3/MnBi2Te4 ratio constant or vice versa. We achieve this by creating atomically engineered sandwich structures composed of Bi2Te3 and MnBi2Te4 layers. We show that the AFM order is exclusively determined by the Mn-Mn distance whereas the FM order depends only on the overall Bi2Te3/MnBi2Te4 ratio regardless of the distance between the MnBi2Te4 layers. Our results shed light on the origins of the AFM and FM orders and provide insights into how to manipulate magnetic orders not only for the MnBi2Te4-Bi2Te3 system but also for other magneto-topological materials.