Spin transport properties based on spin gapless semiconductor CoFeMnSi

摘要

Spin gapless semiconductors have been regarded as the most promising candidates for spin injection materials due to the complete (100%) spin polarization and the conductivity between half-metals and semiconductors. To explore the potential spintronic applications of the quaternary Heusler alloy CoFeMnSi (CFMS), a recently fabricated spin gapless semiconductor with a high Curie temperature of 620 K, we design the GaAs/CFMS heterostructure and the CFMS/GaAs/CFMS magnetic tunnel junction (MTJ). It is found from the first-principles calculations combined with nonequilibrium Green's function that the heterostructure exhibits an excellent spin filtering effect and spin diode effect and the MTJ has a large tunnel magnetoresistance ratio (up to 2 × 10~3), which are explained from the calculated spin-dependent band structure and transmission spectrum. These perfect spin transport characteristics make CFMS a promising candidate for spintronic applications.