Effects of the Hubbard U correction on the electronic and magnetic properties of the tetragonal V2P2 sheet

Abstract

A recent theoretical work predicted the orthorhombic phase of the V₂P₂ sheet with the half-metallic electronic property using a linear combination of atomic orbitals (LCAO) basis set based on density functional theory (DFT). However, in the plane-wave DFT method, the tetragonal (t) V₂P₂ phase is the ground state structure. The total energy of the optimized tetragonal V₂P₂ is 0.91 eV per cell lower than that of the orthorhombic phase. Herein, we investigated the effects of Hubbard U correction onthe electronic, magnetic, and adsorption properties of the t-V₂P₂ sheet. The t-V₂P₂ sheet is found to be dynamically and mechanically stable. The t-V₂P₂ sheet prefers an antiferromagnetic ground state with an indirect narrowed bandgap of 0.23 eV. The estimated electron mobility in the t-V₂P₂ sheet at room temperature is approximately 24 times that of a hole. The t-V₂P₂ sheet exhibits a sizable magnetic anisotropy (MAE) of 69.63 μeV per V atom with in-plane magnetization. Mean-field approximation based on the 2D classical Heisenberg model predicts a high Néel temperature (T_N) of the t-V₂P₂ sheet up to 1263 K. The Li atom adsorption on the t-V₂P₂ sheet shows a transition from semiconductor to metal. Also the Li–V₂P₂ system has a residual integer magnetic moment of 1 μ_B. Due to strong steric coulomb repulsion, the minimum diffusion energy barrier (E_a) for the Li-ion on the t-V₂P₂ surface is high enough to make the Li atom immobile. Our findings demonstrate the potential of the t-V₂P₂ sheet for antiferromagnetic spintronics and sensing applications.