A generic dual d-band model for interlayer ferromagnetic coupling in a transition-metal doped MnBi2Te4 family of materials†
Huisheng Zhang,Jingjing Zhang,Yaling Zhang,Wenjia Yang,Yingying Wang,Xiaohong Xu,Feng Liu
Nanoscale Pub Date : 08/23/2022 00:00:00 , DOI:10.1039/D2NR03283J
Abstract

Realization of ferromagnetic (FM) interlayer coupling in magnetic topological insulators (TIs) of the MnBi2Te4 family of materials (MBTs) may pave the way for realizing the high-temperature quantum anomalous Hall effect (high-T QAHE). Here we propose a generic dual d-band (DDB) model to elucidate the energy difference (ΔE = EAFMEFM) between the AFM and FM coupling in transition-metal (TM)-doped MBTs, where the valence of TMs splits into d-t2g and d-eg sub-bands. Remarkably, the DDB shows that ΔE is universally determined by the relative position of the dopant (X) and Mn d-eg/t2g bands, Image ID:d2nr03283j-t1.gif. If ΔEd > 0, then ΔE > 0 and the desired FM coupling is favored. This surprisingly simple rule is confirmed by first-principles calculations of hole-type 3d and 4d TM dopants. Significantly, by applying the DDB model, we predict the high-T QAHE in the V-doped Mn2Bi2Te5, where the Curie temperature is enhanced by doubling of the MnTe layer, while the topological order mitigated by doping can be restored by strain.

Graphical abstract: A generic dual d-band model for interlayer ferromagnetic coupling in a transition-metal doped MnBi2Te4 family of materials