| Au-MgB2-Au纳米结点的负微分电阻效应 |
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| 引用本文： | 柳福提,;程艳,;陈向荣. Au-MgB2-Au纳米结点的负微分电阻效应[J]. 化学物理学报(中文版), 2014, 0(4): 407-411 |
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| 作者姓名： | 柳福提, 程艳, 陈向荣 |
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| 作者单位： | [1]宜宾学院物理与电子工程学院,宜宾644000; [2]宜宾学院计算物理四川省高校重点实验室,宜宾644000; [3]四川大学物理科学与技术学院,成都610064 |
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| 基金项目： | V. ACKNOWLEDGMENTS This work was supported by the National Natural Science Foundation of China （No.11174214 and No.11204192）, the Research Project of Education Department in Sichuan Province （No.13ZB0207）, and Scientific Research Project of Yibin University （No.2013YY05）. |
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| 摘 要： | 运用密度泛函理论结合非平衡格林函数的方法对MgB2直线原子链与两半无限Au（100）电极构成纳米结点的电子输运特性进行了第一性原理计算．在模拟Au-MgB2-Au纳米结点的拉伸过程中，计算了结点在不同距离下的结合能与电导．结果发现结点的Au-B键长为1．90A，B-Mg键长为2．22A时，结合能最大，结构最稳定，此时结点平衡电导为0．51G0（G0=2e^0／h）．通过计算投影态密度发现电子通过结点时主要是通过B、Mg原子的px和py电子轨道形成的π键进行传输的．在-1．5～1．5V的电压范围内，结点的电流-电压近似为线性关系，表现出类似金属的导电性质，而当正负电压高于15V时，电流对称性逐渐减小，即存在负微分电阻效应，从不同电压下透射谱的变化对负微分电阻现象进行了分析与讨论．
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| 关 键 词： | 电子输运 MgB2原子链 负微分电阻 |
Negative Differential Resistance of Au-MgB2-Au Nanoscale Junctions |
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| Affiliation: | Fu-ti Liu , Yan Cheng, Xiang-rong Chen(1. College of Physics and Electronic Engineering, Yibin University, Yibin 644000, China 2. Computational Physics Key Laboratory of Sichuan Province of Yibin University, Yibin 544000, China 3. College of Physical Science and Technology, Sichuan University, Chengdu 510054, China) |
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| Abstract: | The electron transport of linear atomic chain trodes was investigated by using the density Green＇s function method. We have calculated of MgB2 sandwiched between Au（100） elecfunctional theory with the non-equilibrium the corresponding cohesion energy and conductance of junctions in different distance. It is found that, at the equilibrium position, the Au-B bond-length is 1.90 A, the B-Mg bond-length is 2.22 A, and the equilibrium conductance is 0.51G0 （Go=2e^2/h）. The transport channel is almost formed by the π antibonding orbitals, which was made up of the Px and Py orbital electrons of B and Mg atoms. In the voltage range of -1.5 to 1.5 V, the junctions show the metallic behaviors. When the voltage is larger than 1.5 V, the current decreases gradually and then negative differential resistance appears almost symmetrically on both positive and negative bias. |
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| Keywords: | Electronic transport MgB2 atomic chain Negative differential resistance |
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