First-principles study of the tunnel magnetoresistance effect with Cr-doped RuO2 electrode

We investigate the functionality of the $\mathrm{Cr}$-doped ${\mathrm{RuO}}_{2}$ as an electrode of the magnetic tunnel junction (MTJ), motivated by a recent experiment showing that $\mathrm{Cr}$ doping into rutile-type ${\mathrm{RuO}}_{2}$ is an effective tool to easily control its antiferromagnetic order and the resultant magnetotransport phenomena. We perform first-principles calculation of the tunnel magnetoresistance (TMR) effect in the MTJ based on the $\mathrm{Cr}$-doped ${\mathrm{RuO}}_{2}$ electrodes. We find that a finite TMR effect appears in the MTJ originating from the momentum-dependent spin splitting in the electrodes, which suggests that ${\mathrm{RuO}}_{2}$ with Cr doping will function effectively as the electrode of the MTJ. We also show that this TMR effect can be qualitatively captured by the local density of states inside the tunnel barrier.