Electronic structure and static dielectric response of Ba(Mn1/3Nb2/3)O3 from first principles

► Ba(Mn1/3Nb2/3)O3 is a Mott-Hubbard insulator characterized by Mn(eg)-Nb(t2g) gap. ► The dielectric response depends on both the Ueff at Mn 3d and Nb 4d orbitals. ► Dielectric dependence is explained by charge transfer among neighbor atoms.