Au-Si-Au结点电子输运性质的第一性原理计算

采用密度泛函理论和非平衡格林函数相结合的方法对Au(100)-Si-Au(100) 系统左侧对顶位、右侧对空位的纳米结点的电子输运性质进行了理论模拟计算, 结果得到纳米结点的电导随电极距离(d_z)增大而减小. 在d_z =9.72 Å时, 结点的结合能最低, 结构最稳定, 此时电导为1.227G₀ (G₀=2e²/h), 其电子输运通道主要是Si原子的p_x, p_y和 p_z轨道电子形成的最高占居轨道共振峰; 在外偏压下, 电流-电压曲线表现出线性特征; 随着外加正负电压的增大, 电导略有减小, 且表现出不对称性的变化.关键词：硅原子电子输运密度泛函理论非平衡格林函数

First-principles calculations of the electronic transport in Au-Si-Au junctions

The transport property of silicon sandwiched between Au (100) and Au (100) is investigated with a combination of density functional theory and non-equilibrium Green's function method. It is found that the conductance decreases with distance increasing. When d_z =9.72 Å, the structure of junctions is the most stable and the conductance is 1.227G₀ (G₀=2e²/h) , which is contributed by the p_x, p_y and p_z electron orbits of silicon atom. The I-V curve of junctions in stable station show linear characteristics under external bias vottage. With the increase of an external positive and negative voltage, the conductance decreases slightly, and the asymmetry change appears.
Keywords：silicon atomelectronic transportdensity functional theorynon-equilibrium Green's function