Independent-Band Tight-Binding Parameters for Fe–MgO–Fe Magnetic Heterostructures
Independent-Band Tight-Binding Parameters for Fe–MgO–Fe Magnetic Heterostructures
复制标题
Fe-MgO-Fe 磁性异质结构的独立能带紧束缚参数
DOI：
10.1109/tnano.2009.2037221
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发表时间：
2011
影响因子：
2.4
通讯作者：
Hassan Raza
中科院分区：
文献类型：
--
作者：
T. Raza;Hassan Raza
我们提出了一个计算效率高，可转移的独立带紧束缚模型（IBTB）的自旋极化输运异质结的努力捕捉带结构的影响。作为一个例子，我们应用它来研究通过Fe-MgO-Fe（100）磁性隧道结器件的输运。我们提出了一种新的方法来提取合适的紧束缚参数的材料，通过使用能量分辨的传输作为基准，这固有的带结构效应在2-D横向布里渊区。首次提出了bcc结构Fe（100）不同对称能带的IBTB参数，并与MgO隧道势垒的类Δ1和类Δ5能带的可转移紧束缚参数进行了补充.非平衡绿色函数的形式主义，然后被用来计算的传输特性，如J-V特性，电压依赖性，和势垒宽度依赖的隧道磁阻比被定量捕获，并与从头计算方法中观察到的趋势相匹配。
We present a computationally efficient and transferable independent-band tight-binding model (IBTB) for spin-polarized transport in heterostructures with an effort to capture the band structure effects. As an example, we apply it to study the transport through Fe-MgO-Fe(100) magnetic tunnel junction devices. We propose a novel approach to extract suitable tight-binding parameters for a material by using the energy resolved transmission as the benchmark, which inherently has the band structure effects over the 2-D transverse Brillouin zone. The IBTB parameters for various symmetry bands for bcc Fe(1 0 0) are first proposed which are complemented with the transferable tight-binding parameters for the MgO tunnel barrier for the Δ1-like and Δ5-like bands. The nonequilibrium Green's function formalism is then used to calculate the transport features like J-V characteristics, voltage dependence, and the barrier width dependence of the tunnel magnetoresistance ratio are captured quantitatively, and the trends match well with the ones observed in ab initio methods.