Correlation-induced charge ordering in the metal-insulator transition of Ru-doped tetragonal CrO2

[Display omitted] •The electronic and magnetic properties of pure and 50% Ru-doped CrO2 are studied.•CrO2 encounters half-metal to metal transition at 50% Ru doping.•The doped compound Cr0.5Ru0.5O2 is ferrimagnetic in nature.•Cr0.5Ru0.5O2 encounters metal-insulator transition (MIT) at U = 6 eV exhibiting ferromagnetism.•The origin of metallic ferrimagnetic property, MIT and ferromagnetism of Cr0.5Ru0.5O2 are investigated sequentially. The electronic and magnetic properties of Ru-doped tetragonal CrO2 have been investigated by employing density functional theory (DFT). The host material encounters half-metal to metal transition at 50% Ru substitution for Cr. The Ru addition increases the electrical conductivity by adding free electrons into the minority spin channel near EF. The doped material Cr0.5Ru0.5O2 exhibits ferrimagnetic behaviour with a saturation magnetic moment of 0.8μB. Eventually, Cr0.5Ru0.5O2 encounters metal–insulator transition (MIT) at U = 6 eV showing ferromagnetism. It is revealed for the first time that the segregation of electron from Ru-4dt2g to Cr-3dt2g orbital induces Cr3+–Ru5+ charge ordering, which triggers MIT in Cr0.5Ru0.5O2 that is accompanied by weak static but strong dynamical electron correlation effect arising from on-site Coulomb interaction U = 6 eV. Additionally, strong Hund’s coupling between localized Cr-t2g and Ru-dxy orbitals is responsible for the ferromagnetic behaviour of Cr0.5Ru0.5O2.