Half-metallic ferromagnetism in alkaline earth selenides by first principles calculations

The possibility of half-metallic ferromagnetism in alkaline earth selenides (ASe: A = Mg, Ca, Sr and Ba) with nonmagnetic sp elements such as B, C and N as dopants for various concentrations have been investigated using tight binding linear muffin tin orbital (TB-LMTO) method within the frame work of density functional theory (DFT). Half-metallic ferromagnetism is observed in C- and N-doped alkaline earth selenides at anion site with a total magnetic moment of 2.00 mu(B) and 1.00 mu(B) per formula unit respectively. B does not induce ferromagnetism in alkaline earth selenides except for BaSe. The total energy calculations show that the ferromagnetic state is more stable as compared to nonmagnetic state at their equilibrium volume. Furthermore, equilibrium lattice constant, local magnetic moment, half-metallic gap and heat of formation have been calculated. Electronic band structure and density of states calculations show that the spin polarization of 2p states of C- and N-dopants around the Fermi level are responsible for ferromagnetism in these compounds. (C) 2011 Elsevier B.V. All rights reserved.