Several magnetic semiconductors based on the quaternary Heusler compounds

The successful injection of spin-polarized current into a semiconductor has been expected for a long time in spintronics.[1] The most promising way to achieve it is the use of spin filter materi-als(SFMs), which are magnetic semiconductors.[2] The diluted magnetic semiconductors (DMSs) such as Ga1-xMnxAs can keep both semiconducting and magnetic behavior. However, this strategy is limited by the low Curie temperatures Tc, which is lower than the room temperature.[2] It is reported that Heusler compounds usually have high Tc. If we can find magnetic semiconductors in Heusler compounds, we may get the high Tc SFMs. The quaternary Heusler compounds have the most complexest ingredient in the Heusler compounds, which means that they may have more possibilities. Employing ab-initio electronic structure calculations within density functional theory, we show that the quaternary Heusler compounds FeNbVAl, FeNbVGa are magnetic semiconductors. We find a rule of searching for magnetic semiconductors by contrasting the band structure of V2FeAl, FeNbVAl, Nb2FeAl, and FeVNbAl. FeNbVGa can also meet this rule. Under this rule we find FeTiCrAl is also magnetic semiconductor. Though we have not found more evidence by now, we hope our finding help researchers find more magnetic semiconductors.