Structural and electronic properties of V₂O₅ and MoO₃ bulk and ultrathin layers

The structural and electronic properties of bulk, monolayer and ultrathin films of V$_2$O$_5$ and MoO$_3$ layered oxides have been studied with first-principles density functional theory calculations including Van der Waals dispersion corrections. Specific DFT+U functionals have been tested in order to properly reproduce geometry, band-gap, static dielectric constant, and formational enthalpies of the two materials. The mono-, and multi-layers are cleaved along the <001> and <010> stable crystallographic orientations for V2O5 and MoO3, respectively. At least three layers are needed for both materials in order to recover bulk-like properties. Spin-orbit effects have been incorporated in our prediction, but they show marginal effects.