Recent advances in Dirac spin-gapless semiconductors

Spin-gapless semiconductors (SGSs), the new generation of spintronic materials, have received increasing attention recently owing to their various attractive properties such as fully spin-polarization and high carrier mobility. Based on their unique band structures, SGSs can be divided into two types: parabolic and Dirac-like linear. The linear-type SGSs, also called Dirac SGSs (DSGSs), have real massless fermions and dissipation-less transport properties, and thus are regarded as promising material candidates for applications in ultra-fast and ultra-low-power spintronic devices. DSGSs can be further classified into p-state type or d-state type depending on the degree of contribution of either the p-orbitals or d-orbitals to the Dirac states. Considering the importance of the research field and to cover its fast development, we reviewed the advances in DSGSs and proposed our own viewpoints. First, we introduced the computational algorithms of SGSs. Second, we found that the boundaries between DSGSs and Dirac half-metals were frequently blurred. Therefore, a simple classification is proposed in this work. Third, we collected almost all the studies on DSGSs published in the past six years. Finally, we proposed new guidance to search for DSGSs among 3D bulk materials on the basis of our latest results.