Doping induced multiferroicity and quantum anomalous Hall effect in $α$-In$_2$Se$_3$ thin films

Zhiqiang Tian; Jin-Yang Li; Tao Ouyang; Chao-Fei Liu; Ziran Liu; Si Li; Anlian Pan; Mingxing Chen

doi:10.1063/5.0179956

paper

Doping induced multiferroicity and quantum anomalous Hall effect in $α$ -In $_{2}$ Se $_{3}$ thin films

arXiv:2402.09770 · doi:10.1063/5.0179956

Abstract

In flat-band materials, the strong Coulomb interaction between electrons can lead to exotic physical phenomena. Recently, $α$ -In $_{2}$ Se $_{3}$ thin films were found to possess ferroelectricity and flat bands. In this work, using first-principles calculations, we find that for the monolayer, there is a Weyl point at $Γ$ in the flat band, where the inclusion of the spin-orbit coupling opens a gap. Shifting the Fermi level into the spin-orbit gap gives rise to nontrivial band topology, which is preserved for the bilayer regardless of the interlayer polarization couplings. We further calculate the Chern number and edge states for both the monolayer and bilayer, for which the results suggest that they become quantum anomalous Hall insulators under appropriate dopings. Moreover, we find that the doping-induced magnetism for In $_{2}$ Se $_{3}$ bilayer is strongly dependent on the interlayer polarization coupling. Therefore, doping the flat bands in In $_{2}$ Se $_{3}$ bilayer can also yield multiferroicity, where the magnetism is electrically tunable as the system transforms between different polarization states. Our study thus reveals that multiferroicity and nontrivial band topology can be unified into one material for designing multifunctional electronic devices.

arXiv comment6 pages, 4 figures

Doping induced multiferroicity and quantum anomalous Hall effect in α-In2​Se3​ thin films

Abstract

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Doping induced multiferroicity and quantum anomalous Hall effect in $α$ -In $_{2}$ Se $_{3}$ thin films