论文标题
（111）与SRTIO $ _3 $障碍物的带折叠驱动的高隧道磁力磁力比（111）
Band-folding-driven high tunnel magnetoresistance ratios in (111)-oriented junctions with SrTiO$_3$ barriers
论文作者
论文摘要
我们从理论上研究了（111）面向磁性隧道连接（MTJS）的隧道磁磁性效应（TMR）效应，其中Srtio $ _ {3} $ brailiers，co/srtio $ _ {3} $/co/co/co/co/co/co（111）和ni/srtio $ $ $ $ $ $ _ {3} $/ni（111）。我们的分析结合了第一原理的计算和Landauer公式，表明基于CO的MTJ的TMR比高于500％，而基于NI的MTJ的TMR比具有较小的值（290％）。由于SRTIO $ _ {3} $的平面晶格周期性大约是FCC CO（NI）原始单元的两倍，因此CO（Ni）的原始频带折叠在$ k_x $ -k_y $ $ k_y $平面与MTJ SuperCell的$ ab $平面相对应。我们发现，该频带折叠在$λ_1$ of CO（NI）中提供了半金属的频段结构，并且此类半金属$λ_1$状态的相干隧道产生了高的TMR比率。我们还透露，基于共同和Ni的MTJ之间的TMR比率的差异可以通过FERMI级别的$λ_1$频段中的不同$ s $ - 轨道权重来理解。
We theoretically study the tunnel magnetoresistance (TMR) effect in (111)-oriented magnetic tunnel junctions (MTJs) with SrTiO$_{3}$ barriers, Co/SrTiO$_{3}$/Co(111) and Ni/SrTiO$_{3}$/Ni(111). Our analysis combining the first-principles calculation and the Landauer formula shows that the Co-based MTJ has a high TMR ratio over 500%, while the Ni-based MTJ has a smaller value (290%). Since the in-plane lattice periodicity of SrTiO$_{3}$ is about twice that of the primitive cell of fcc Co (Ni), the original bands of Co (Ni) are folded in the $k_x$-$k_y$ plane corresponding to the $ab$ plane of the MTJ supercell. We find that this band folding gives a half-metallic band structure in the $Λ_1$ state of Co (Ni) and the coherent tunneling of such a half-metallic $Λ_1$ state yields a high TMR ratio. We also reveal that the difference in the TMR ratio between the Co- and Ni-based MTJs can be understood by different $s$-orbital weights in the $Λ_1$ band at the Fermi level.
