Origin of d0 half-metallic characteristic in DO3-type XO3 (X=Li, Na, K and Rb) compounds

•In an attempt to combine the properties of DO3-type and d0 HMFs, XO3 have been designed.•The electronic structures and magnetism of the XO3 have been studied.•The effect of uniform strain on the spin polarization ratio have been tested.•The origin of the d0 HM character have been explained.•Total energy calculation and structure stability have been performed.

Plane-wave pseudo-potential methods based on density functional theory are employed to investigate the electronic structures, magnetic properties of newly designed DO3-type XO3 (X=Li, Na, K and Rb) compounds. Result shows they are d0 HM ferromagnets with total magnetic moment of 5.00 μB. Importantly, the d0 HM characteristic is originated from the polarization of the p-orbitals of O atoms in these hypothetical compounds. The structure stability in the aspects of cohesion energy and formation energy of these four compounds have been tested. The spin-flip gaps of the four XO3 compounds are quite large (>1.00 eV). Furthermore, the d0 HM behavior can be maintained in a wide range of lattice constants.