Strain-induced topological phase transition and enhanced Curie temperature in MnBi2Te4/CrI3 heterojunction

Abstract

By first-principles calculations and Monte Carlo simulations, we investigate the influence of biaxial strain on the band structures, magnetic characteristics, and Curie temperature (${T}_{\mathrm{C}}$) of ${\mathrm{MnBi}}_{2}{\mathrm{Te}}_{4} (\mathrm{MBT})/\mathrm{Cr}{\mathrm{I}}_{3}$ heterojunction. Different from bilayer MBT or ${\mathrm{CrI}}_{3}$ with antiferromagnetic ordering, the interlayer magnetic coupling of $\mathrm{MBT}/\mathrm{Cr}{\mathrm{I}}_{3}$ prefers ferromagnetic ordering. By applying biaxial strain, a phase transition from semiconductor to metal can be found and a band inversion is observed under a strain of $\ensuremath{-}5%$, suggesting the existence of nontrivial topological phase transition. Moreover, magnetic anisotropy energy (MAE) and ${T}_{\mathrm{C}}$ are sensitive to compressive strain rather than tensile strain. The magnitude of MAE is increased ten times in the strain range $\ensuremath{-}5$ to 5%. Meanwhile, the compressive strain enhances the ferromagnetism, leading to a boost of ${T}_{\mathrm{C}}$ about 13.8% up to 91.1 K. Our findings can provide beneficial guidance for designing the spintronic which hosts robust ferromagnetism and improved ${T}_{\mathrm{C}}$.