Robust half-metallicity in Ga1-xMnxP and Ga1-xMnxAs

Theoretical calculations of Ga1-xMnxP and Ga1-xMnxAs (x = 0.125) in the zinc blende phase are presented. The electronic structure and magnetic properties of these compounds are calculated and their correlation is investigated with the lattice compressions. The results show that, both the compounds hold their half-metallic nature, conductor for spin up state and semiconductor for spin down state, with their lattice compressions up to certain critical lattice constants. An abrupt change in the electronic and magnetic properties is observed at these robust transition lattice constants (RTLCs). These compounds loss their integer magnetic moments (4 μβ) and tremendous decrease in the bandgaps (spin down states) start at these critical lattice constants and hence the materials transform from half-metals to degenerate semiconductors. The calculated RTLC for Ga0.875Mn0.125P is 5.14 Å and for Ga0.875Mn0.125As is 5.25 Å. The possible compression in the lattice constants from their relaxed states, while maintaining their half-metallic nature, is up to 6% for Ga0.875Mn0.125P and 8% for Ga0.875Mn0.125As. The feasibility of the growth of these compounds on different substrates on the basis of the variation in the lattice constants is also discussed.

► Spintronics, a new field of spin based electronics have attracted great attention in the recent years.
► The challenging tasks for materials scientists are to investigate compounds with 100% spin polarization at Fermi level.
► The doping also transforms the indirect bandgap of GaP into direct bandgap material, which is optically active.
► Robustness of half Metallicity in GaMnP and GaMnAs with their lattice compressions is investigated.