Role of electronic correlation effect on charge ordering in β-V2OPO4

Abstract

Charge ordering, the ordering of transition metal ions with different oxidation states, is a celebrated feature in mixed valent transition metal oxides, leading to intriguing electronic and magnetic phenomena. In this work, we exploited the electronic and magnetic properties of the charge ordered insulator β-V2OPO4 within the monoclinic C2/c phase by means of first-principles calculations. Our results demonstrated that the AFM-II ordering, in which spin on all V2+ atoms are parallel and so do the spin on all V3+ atoms while these two spin sublattices are antiparallel to each other, experimentally observed, is the magnetic ground state, irrespective of whether the correlation was adopted or not. Furthermore, our theoretical results highlight the importance role of electronic correlation in reasonably reproducing the electronic properties of β-V2OPO4, including the charge ordering, metal-insulator transition, spin orientation as well as structural distortion. The charge ordering scenario has been analyzed in details in terms of Bader charge, magnetic moments, octahedron volume difference and distortion index. In addition, the phase diagram has been established with respect to correlation strengths.