J Phys Condens Matter. 2014 Jan 8;26(1):015002. doi: 10.1088/0953-8984/26/1/015002. Epub 2013 Nov 22.
We report ab initio simulations of quantum transport properties of Fe/MgO/Fe trilayer structures with FeO0.5 buffer iron oxide layer, where on-site Coulomb interaction is explicitly taken into account by local density approximation + Hubbard U approach. We show that on-site Coulomb repulsion in the iron-oxygen layer can cause a dramatic drop of the tunnel magnetoresistance of the system. We present an understanding of microscopic details of this phenomenon, connecting it to localization of electronic states of particular symmetry, which takes place in the buffer Fe-O layer, when on-site Coulomb repulsion is introduced. We further study the possible influence of the symmetry reduction in the buffer Fe-O layer on the transport properties of the Fe/MgO/Fe interface.
我们报告了具有 FeO0.5 缓冲氧化铁层的 Fe/MgO/Fe 三层结构的量子输运性质的从头算模拟，其中通过局域密度近似+ Hubbard U 方法明确考虑了局域库仑相互作用。我们表明，铁-氧层中的局域库仑排斥作用会导致系统的隧道磁电阻急剧下降。我们对这种现象的微观细节有了一个理解，将其与特定对称性的电子态的局域化联系起来，当引入局域库仑排斥作用时，这种局域化会发生在缓冲 Fe-O 层中。我们进一步研究了缓冲 Fe-O 层中对称性降低对 Fe/MgO/Fe 界面输运性质的可能影响。
