Electronic correlation effects on zinc-ion migration in V2O5: A DFT+U study

Abstract

We investigate the role of on-site Coulomb interactions in determining the structural, electronic, and ion transport properties of Zn_0.5V${}_2$O${}_5$ using density functional theory with Hubbard $U$ correction (DFT+$U$). We analyze the system’s properties as a function of the Hubbard parameter and compute its ab initio value using density functional perturbation theory. Our calculations reveal a metal-to-insulator transition in Zn_0.5V${}_2$O${}_5$ at $U\approx 2\mathrm{eV}$, accompanied by the emergence of antiferromagnetic ordering on vanadium sites and significant structural modifications. Most importantly, we demonstrate that Zn ion migration barriers exhibit non-monotonic dependence on the correlation strength. While the migration barrier (0.376 eV) calculated using the ab initio $U$ value appears similar to that (0.353 eV) from nonmagnetic DFT calculations, the underlying electronic and magnetic structures differ fundamentally, highlighting the critical importance of properly accounting for correlation effects in this system. Furthermore, our differential charge density analysis reveals that the change in localization of electronic states with increasing $U$ strongly affects the interaction between the Zn ion and the host structure, playing a crucial role in determining the migration behavior.