<i>Ab initio</i> study of magnetoresistance effect in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msub> <mml:mtext>Mn</mml:mtext> <mml:mn>3</mml:mn> </mml:msub> <mml:mtext>Sn</mml:mtext> <mml:mo>/</mml:mo> <mml:mtext>MgO

The electric current flowing through antiferromagnets can be spin-polarized when their magnetic structures break the macroscopic time-reversal symmetry, which leads to the emergence of the tunnel magnetoresistance (TMR) effect in the antiferromagnetic tunnel junction. In this study, the authors calculation the TMR effect from first-principles with the noncollinear antiferromagnet Mn${}_{3}$Sn as the electrode, and MgO, a typical barrier material, as the insulating spacer. They show that Mn${}_{3}$Sn/MgO/Mn${}_{3}$Sn junctions exhibit a sizable TMR effect owing to the spin splitting of Mn${}_{3}$Sn and the screening effect of MgO. This work will serve as a reasonable benchmark for further development of the antiferromagnetic TMR effect.