Origin of ferromagnetism in the half-Heusler XRbCs compounds (X=N, P and As)

•Ab initio prediction on the magnetic properties of XRbCs half-Heusler, X=N, P and As.•These hypothetical compounds are half-metal ferromagnets in their stable structure.•The magnetism is due to the polarization p-states of X= N, P and As.•The half-metallicity is maintained in a wide range of lattice constants.

A density functional theory was used to study the origin of ferromagnetism in the half-Heusler XRbCs compounds (where X  =N, P, and As). The results predict a stable atomic arrangement with a ferromagnetic order. The spin-polarized calculations give a total magnetic moment of about 1μB. The most important property in these hypothetical compounds is that the half-metallicity is originated from the polarization of the p-orbitals originated from N, P, and As atoms. We also find that the half-metallicity is maintained on a wide range of lattice constants and therefore offers the possibility to grow such materials on various semiconductor substrates.