First principles study on d~0 half-metallic properties of full-Heusler compounds RbCaX2(X=C,N,and O)

A first-principles approach is employed to study the structural,electronic,and magnetic properties of Rb Ca X2(X = C,N,and O) full-Heusler compounds.It is observed that Rb Ca N2 and Rb Ca O2 are new d0half-metals with an integer magnetic moment of 3 μBand 1 μBin their ferrimagnetic ground states,respectively,while Rb Ca C2 is a common metallic compound.Analysis of the density of states of these compounds indicates that the magnetic moment and furthermore,the half-metallicity primarily originate from the spin-polarization of the p-like states of N and O atoms.The half-metallic(HM) gaps of Rb Ca N2 and Rb Ca O2 are notably large;thus,the half-metallicity is robust against lattice distortion.Such materials are suitable to be grown on various semiconductor substrates.In addition,for Rb Ca N2 and Rb CaO 2,four possible terminations of the surface are also calculated.