Iron oxyhalides monolayers with excellent optical anisotropic properties and large anisotropic carrier mobility

Developing two-dimensional layered materials is highly desirable for nanoscale device applications. Antiferromagnetic materials have attracted considerable attention through their absence of production of parasitic stray fields, ultrafast dynamics, and the generation of large magnetotransport effects. Here, based on first-principles calculations, we demonstrate a series of promising two-dimensional semiconductors in the family of iron oxyhalides FeOX (X = F, Cl, Br, I) with antiferromagnetism, anisotropic optical properties and large carrier mobility. Combined with appropriate gaps, this renders FeOX monolayers with high absorption coefficient up to $3.90\times {10}^5{\mathrm{cm}}^{-1}$ in the visible region. In addition, due to their large band dispersion, FeOX monolayers are also found to harbor considerably high carrier mobilities, especially for FeOBr ($6.84\times {10}^3{\mathrm{cm}}^2{V}^{-1}{s}^{-1}$), suggesting their enormous potential for optoelectronic fields. All of these discoveries make these FeOX monolayers compelling materials for next-generation nanoscale photovoltaic device.