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arXiv · 2406.00293

Ferroelectricity in oxygen-terminated 2D carbides of lanthanide elements

Lin Han·Wencong Sun·Pingwei Liu·Xianqing Lin·Dan Liu·David Tomanek
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Abstract

We investigate the properties of oxygen-functionalized carbides of lanthanide elements with the composition M2CO2 (M=Gd, Tb,Dy) that form two-dimensional (2D) structures. Our ab initio calculations reveal that oxygen termination turns M2C monolayers into semiconductors with two dynamically stable phases. Of these, the energetically favored alpha-phase becomes ferroelectric, whereas the beta-phase turns anti-ferroelectric. Applying in-plane biaxial strain may transform one phase into the other, changes the ferroelectric polarization of the alpha-phase in a linear fashion, and modifies the size and nature of the fundamental band gap from direct to indirect. The structure with a direct band gap exhibits in-plane isotropic electronic and optical properties. This previously unexplored class of systems also exhibits excellent photon absorption in the ultraviolet range.

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Lin Han, Wencong Sun, Pingwei Liu, Xianqing Lin, Dan Liu, David Tomanek. 2024-06-01. Ferroelectricity in oxygen-terminated 2D carbides of lanthanide elements. https://doi.org/10.1103/physrevmaterials.8.054005

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