We studied the applicability of Heusler alloys Mn₂RuZ (Z = Al, Ga, Ge, Si) to the electrode materials of MgO-based magnetic tunnel junctions. All these alloys possess Hg₂CuTi-type inverse Heusler alloy structure and ferrimagnetic ground state. Our study reveals the half-metallic electronic structure with highly spin-polarized Δ₁ band, which is robust against atomic disorder. Next we studied the electronic structure of Mn₂RuAl/MgO and Mn₂RuGe/MgO heterojunctions. We found that the MnAl- or MnGe-terminated interface is energetically more favorable compared to the MnRu-terminated interface. Interfacial states appear at the Fermi level in the minority-spin gap for the Mn₂RuGe/MgO junction. We discuss the origin of these interfacial states in terms of local environment around each constituent atom. On the other hand, in the Mn₂RuAl/MgO junction, high spin polarization of bulk Mn₂RuAl is preserved independent of its termination.

我们研究了 Heusler 合金 Mn ₂ Ru Z ( Z = Al, Ga, Ge, Si) 对 MgO 基磁性隧道结电极材料的适用性。这些合金均具有Hg ₂ CuTi型逆Heusler合金结构和亚铁磁基态。我们的研究揭示了具有高度自旋极化 Δ ₁带的半金属电子结构，该结构对原子无序具有鲁棒性。接下来我们研究了 Mn ₂ RuAl/MgO 和 Mn ₂的电子结构RuGe/MgO 异质结。我们发现，与以 MnRu 为终端的界面相比，以 MnAl 或 MnGe 为终端的界面在能量上更有利。Mn ₂ RuGe/MgO 结的少数自旋能隙中的费米能级出现界面态。我们根据每个组成原子周围的局部环境来讨论这些界面态的起源。另一方面，在 Mn ₂ RuAl/MgO 结中，块体 Mn ₂ RuAl 的高自旋极化保持独立于其终止。