Structural, Electronic, Magnetic, and Optical Properties of Ir(2)ScZ (Z = Si, Ge, Sn) Full-Heusler Compounds: A First-Principles Study

摘要

The structural, electronic, magnetic, and optical properties of the full-Heusler compounds Ir(2)ScZ (Z = Si, Ge, Sn) have been investigated using density functional theory (DFT). For these compounds, the structure of type a is the most stable and their ferromagnetic phases are more stable rather than their antiferromagnetic or nonmagnetic phases. Spin-polarized calculations reveal that Ir2ScSi and Ir2ScSn follow the Slater-Pauling rule and have an integer magnetic moment of 1.00 mu(B) at equilibrium lattice constant, while for Ir2ScGe it is 0.98 mu(B). The compound Ir2ScSi shows half-metallic properties at equilibrium lattice constant and under stress. Ir2ScGe and Ir2ScSn show half-metallic properties under stress. The Curie temperature of Ir2ScSi, Ir2ScGe, and Ir2ScSn is calculated to be 654.5 K, 537.6 K, and 633.4 K, respectively, and the half-metallic bandgaps are found to be 0.41 eV and 0.09 eV for Ir2ScSi and Ir2ScSn, respectively. The high Curie temperature and the half-metallic properties under stress of these compounds show that they are good candidates for use in spintronic devices and spin valves. The optical properties of Ir2ScSi at equilibrium lattice constant a(0) and for Ir2ScGe and Ir2ScSn at a(4) = a(0) - 4%a(0) are investigated. For these compounds, rather high absorption occurs in the infrared region.