Possible half metallic antiferromagnet in a hole-doped perovskite cuprate predicted by first-principles calculations.

We formulate a scheme to realize a half metallic antiferromagnet (HMAFM), a material conductive in only one spin channel while exhibiting zero macroscopic magnetism, by doping carrier into a class of cuprates. The working rationale is exhibited as taking advantage of Hubbard repulsion of d electrons of Cu atoms and the charge-transfer effect from the associated O ligand to fully polarize the spin of a doped carrier. Specifically, doping one hole into the insulating ferrimagnet Sr8CaRe3Cu4O24 by replacing one of the eight Sr atoms by one Rb atom is predicted to achieve a HMAFM, presumably with room-temperature operation. Since the working rationale is the strong correlations of electrons commonly encountered in cuprates, it is expected that the present findings can shed light on a new way to develop a HMAFM.