Room-temperature d0 ferromagnetism in carbon-doped Y2O3 for spintronic applications: A density functional theory study

Through density functional theory simulations with the generalized gradient approximation, confirmed by the more sophisticated hybrid functional, we predict the triggering of ${d}^{0}$ ferromagnetism in C doped ${\mathrm{Y}}_{2}{\mathrm{O}}_{3}$ at a hole density of $3.36\ifmmode\times\else\texttimes\fi{}{10}^{21}\phantom{\rule{0.16em}{0ex}}\mathrm{c}{\mathrm{m}}^{\ensuremath{-}3}$ (one order less than the critical hole density of ZnO) having magnetic moment of $2.0\phantom{\rule{0.16em}{0ex}}{\ensuremath{\mu}}_{B}$ per defect with ferromagnetic coupling large enough to promote room-temperature ferromagnetism. The persistence of ferromagnetism at room temperature is established through computation of the Curie temperature by the mean field approximation and ab initio molecular dynamics simulations. The induced magnetic moment is mainly contributed by the $2p$ orbital of the impurity C and the $2p$ orbital of O and we quantitatively and extensively demonstrate through the analysis of density of states and ferromagnetic coupling that the Stoner criterion is satisfied to activate room-temperature ferromagnetism. As the system is stable at room temperature, C doped ${\mathrm{Y}}_{2}{\mathrm{O}}_{3}$ has feasible defect formation energy and ferromagnetism survives for the choice of hybrid exchange functional, and at room temperature we strongly believe that C doped ${\mathrm{Y}}_{2}{\mathrm{O}}_{3}$ can be tailored as a room-temperature diluted magnetic semiconductor for spintronic applications.