Density-functional method for nonequilibrium electron transport -: art. no. 165401
Density-functional method for nonequilibrium electron transport -: art. no. 165401
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DOI：
10.1103/physrevb.65.165401
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发表时间：
2002-04-15
影响因子：
3.7
通讯作者：
Stokbro, K
中科院分区：
文献类型：
--
作者：
Brandbyge, M;Mozos, JL;Stokbro, K
我们描述了一种从头计算方法，用于计算电子结构，电子输运，和原子上的作用力，原子尺度的系统连接到半无限电极和外加电压偏置。我们的方法是基于密度泛函理论（DFT）的实施以及测试SIESTA方法（它使用非局部范数守恒赝势来描述的核心电子的影响，和有限范围的数值原子轨道的线性组合来描述的价态）。我们完全处理整个系统的原子结构，将接触和电极放在同一个基础上。使用非平衡绿色函数考虑了有限偏置的影响（包括自洽性和静电问题的解决方案）。我们与非平衡绿色的函数表达式更透明的计划涉及的散射态。作为一个例子，该方法被应用到三个系统，我们能够比较我们的结果，早期的从头算DFT计算或实验，我们指出这种方法和现有的计划之间的差异。所考虑的系统是：（i）连接到具有延伸或有限横截面的铝电极的单原子碳线，（ii）单原子金线，以及最后（iii）具有点缺陷的大碳纳米管系统。
We describe an ab initio method for calculating the electronic structure, electronic transport, and forces acting on the atoms, for atomic scale systems connected to semi-infinite electrodes and with an applied voltage bias. Our method is based on the density-functional theory (DFT) as implemented in the well tested SIESTA approach (which uses nonlocal norm-conserving pseudopotentials to describe the effect of the core electrons, and linear combination of finite-range numerical atomic orbitals to describe the valence states). We fully deal with the atomistic structure of the whole system, treating both the contact and the electrodes on the same footing. The effect of the finite bias (including self-consistency and the solution of the electrostatic problem) is taken into account using nonequilibrium Green's functions. We relate the nonequilibrium Green's function expressions to the more transparent scheme involving the scattering states. As an illustration, the method is applied to three systems where we are able to compare our results to earlier ab initio DFT calculations or experiments, and we point out differences between this method and existing schemes. The systems considered are: (i) single atom carbon wires connected to aluminum electrodes with extended or finite cross section, (ii) single atom gold wires, and finally (iii) large carbon nanotube systems with point defects.