摘要:
运用密度泛函理论结合非平衡格林函数的方法,对GaAs团簇与两半无限Au(100)-3×3电极以顶位对顶位、顶位对空位、空位对顶位、空位对空位四种不同耦合形貌构成的Au-GaAs-Au纳米结点电子输运性质进行了理论计算.对结点在不同距离下的结构进行了几何优化,模拟了结点拉伸直至断裂的过程.计算结果得到四种构型结点在两极距离分别为1.389 nm,1.145 nm,1.145 nm,0.861 nm时,结构最稳定.对于各稳定结构, Ga-As键长分别为0.222 nm,0.235 nm,0.227 nm,0.235 nm,其平衡电导分别为2.33 G0,1.20 G0,1.90 G0,1.69 G0,结点具有很好的电子输运性质.在-1.2-1.2 V的电压范围内,所有结点的电流-电压都表现出近线性关系.
Abstract:
Electron transport properties of GaAs cluster, which is sandwiched between two semi-infinite Au(100)-3×3 electrodes in four different anchoring configurations (top-top, top-hollow, hollow-top, hollow-hollow), is investigated using the combination of density functional theory and non-equilibrium Green’s function method. We optimize the geometry of junctions at different distances, simulate the breaking process of Au-GaAs-Au junctions, calculate the cohesion energy and conductance of the junctions as functions of distance dz , and obtain the most stable structure when the distances are set at 1.389 nm, 1.145 nm, 1.145 nm, 0.861 nm, respectively. For stable structures, the Ga-As bond lengths of the junctions is 0.222 nm, 0.235 nm, 0.227 nm, 0.235 nm, respectively. The equilibrium conductances are 2.33 G0, 1.20 G0, 1.90 G0, 1.69 G0,respectively. All junctions have large conductance. In the range of voltage from ?1.2—1.2 V, the I-V curve of the junctions shows linear characteristics.
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