期刊
JOURNAL OF APPLIED PHYSICS
卷 109, 期 2, 页码 -出版社
AMER INST PHYSICS
DOI: 10.1063/1.3525703
关键词
-
资金
- Spanish MICINN [MAT2007-66719-C03-02]
- Research Grants Council of the Hong Kong Special Administrative Region, China [CityU3/CRF/08]
- NSF sponsored Network for Computational Nanotechnology (NCN)
Although the theory of tunnel magnetoresistance (TMR) in Fe/MgO/Fe heterostructures is well known, there is a discrepancy between the values predicted by ab initio calculations with a band gap of 5.2 eV and the ones predicted by other methods, e. g., empirical tight-binding with a band gap of 7.6 eV. To our knowledge, no one has yet used the same theory to explore the reasons behind this discrepancy. In this work, we report a three-dimensional atomistic nonequilibrium Green's function transport model with two set of transferable extended Huckel theory parameters for MgO; one with the experimental band gap of 7.8 eV and the other with the local density approximation of the density functional theory band gap of 5.2 eV. To capture the symmetry filtering property of MgO, we parameterize using the k-resolved orbital projected density of states as the benchmark. We show that the band gap has a significant effect on the barrier width dependence and the bias dependence of the transport quantities. By using the experimental band gap, the TMR is much smaller than the one observed with a band gap of 5.2 eV. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3525703]
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据