Theoretical study on magnetic tunneling junctions with semiconductor barriers CuInSe₂ and CuGaSe₂ including a detailed analysis of band-resolved transmittances

We study spin-dependent transport properties in magnetic tunneling junctions (MTJs) with semiconductor barriers, Fe/CuInSe$_2$/Fe(001) and Fe/CuGaSe$_2$/Fe(001). By analyzing their transmittances at zero bias voltage on the basis of the first-principles calculations, we find that spin-dependent coherent tunneling transport of $\Delta_1$ wave functions yields a relatively high magnetoresistance (MR) ratio in both the MTJs. We carry out a detailed analysis of the band-resolved transmittances in both the MTJs and find an absence of the selective transmission of $\Delta_1$ wave functions in some energy regions a few eV away from the Fermi level due to small band gaps in CuInSe$_2$ and CuGaSe$_2$.