First Principles Study of Structural, Magnetic and Electronic Properties of PbX (X= S and Se) Doped with B, C and N

Six ternary compounds PbA (0.75) M (0.25) (A=S and Se; M=B, C and N) with a NaCl structure were calculated to study the structure, electronic, and magnetic properties of them. The calculations were performed using the first-principles plane wave pseudopotential method within the generalized gradient approximation. The calculations reveal that ferromagnetism can be realized for C- and N-doping while B substitution does not induce magnetism in PbS and PbSe systems. The total energy calculations show that the ferromagnetic state is more stable as compared to a nonmagnetic state at their equilibrium lattices. Spin-dependent electronic band structure, total, and partial densities of state calculations demonstrate that the 2p-states of C- and N-dopants around Fermi level are responsible for ferromagnetism. Furthermore, equilibrium lattice constant, bond length, local magnetic moments, total magnetic moments, and robustness of ferromagnetism have been calculated. Particularly, the negative pressure calculations indicate that C-doping lead chalcogenides can change to half-metallic ferromagnetism materials.