High-throughput screening for spin-gapless semiconductors in quaternary Heusler compounds

Based on high-throughput density functional theory calculations, we performed a systematic screening for spin-gapless semiconductors (SGSs) in quaternary Heusler alloys X X^'Y Z (X , X^', and Y are transition metal elements except Tc, and Z is one of B, Al, Ga, In, Si, Ge, Sn, Pb, P, As, Sb, and Bi). Following an empirical rule, we focused on compounds with 21, 26, or 28 valence electrons, resulting in 12 000 possible chemical compositions. After systematically evaluating the thermodynamic, mechanical, and dynamical stabilities, we have identified 70 so far unreported SGSs, confirmed by explicit electronic structure calculations with proper magnetic ground states, of which 17 candidates have a distance to the convex hull smaller than 0.10 eV/atom. It is demonstrated that all four types of SGSs can be realized, defined based on the spin characters of the bands around the Fermi energy. Type-II SGSs show promising transport properties for spintronic applications. The effect of spin-orbit coupling is investigated, resulting in large anisotropic magnetoresistance and anomalous Nernst effects.