Pressure-induced metallic and magnetic transformation for CuCrP₂S₆ and V-doped CuCrP₂S₆

As one of the important multiferroic materials, CuCrP₂S₆ (CCPS) is distinguished by the emergence of antiferromagnetic (AFM) and antiferroelectric (AFE) orders. However, the research on metallic and magnetic transformation CCPS is relatively scarce. In this work, the interplay of electronic structures and magnetic behavior for two-dimensional multiferroic materials CCPS and V-doped CCPS (CCVPS) under high-pressure were studied by using the first-principles calculations. For CCPS, the AFM order was the ground state, and the Cr-3d orbital configuration was (t_2g)³ (e_g)⁰. As the external pressure increased, the band gap of CCPS decreased. The metallic transformation occurred in CCPS at the pressure of 50 GPa with the collapse of the single-layer ferromagnetic (FM) order. The p-d hybridization between Cr-3d orbitals (and Cu-3d orbitals) and S-3p orbitals gradually enhanced under high-pressure. For CCVPS, the electronic structure of the semiconductor materials was regulated by high-pressure, and the half-metallic transformation was discovered at the pressure of 40 GPa due to the isovalent (V³⁺, Cr³⁺) substitution. In the single layer of CCVPS, the spin magnetic field was produced by the unpaired valence electrons in the Cr-3d and V-3d orbitals, and the magnetic properties were mainly attributed to the Cr and V atoms.