First-principles study on magnetic tunneling junctions with semiconducting CuInSe${}_2$ and CuGaSe${}_2$ barriers

Abstract

We theoretically investigate two different magnetic tunneling junctions (MTJs) with semiconductor barriers, CuInSe${}_2$ (CIS) and CuGaSe${}_2$ (CGS), which are the terminal compounds of recently reported mixed semiconductor barrier, CuIn${}_{1-x}$Ga${}_x$Se${}_2$. To discuss the transport properties of these systems, we analyze complex band structures, magnetoresistance (MR) ratios, and resistance-area products ($RA$) by using first-principles based calculations in combination with the Landauer formula. It is found that the ${\Delta }_1$ wave functions have dominant contributions to the spin-dependent tunneling transport in both CIS- and CGS-based MTJs. We also find that the CGS-based MTJ has a much larger MR ratio and slightly higher $RA$ than those of the CIS-based MTJ, which indicates that a larger MR ratio is expected for a higher Ga concentration $x$ in the CuIn${}_{1-x}$Ga${}_x$Se${}_2$-based MTJs. We further study the relationship between the band gaps in the barriers and MR ratios by changing the Coulomb repulsions in the Cu 3$d$ states of the CIS and CGS. It is shown that the barrier with a larger band gap yields a larger MR ratio. The comparison of MR ratios and $RA$ between the CIS-, CGS-, and MgO-based MTJs are also given.

10 pages, 4 figures

References in corpus (2)

• Bias dependent inversion of tunneling magnetoresistance in Fe/GaAs/Fe tunnel junctions
• Efficient DFT+U calculations of ballistic electron transport: Application to Au monatomic chains with a CO impurity

Cited by in corpus (1)

• Giant interfacial perpendicular magnetic anisotropy in Fe/CuIn${}_{1-x}$Ga${}_x$Se${}_2$ beyond Fe/MgO