汤振兵, 王喜志, 孙亚茹, 马良财. 贵金属合金单原子链结构稳定性的第一性原理研究[J]. 云南大学学报(自然科学版), 2019, 41(6): 1152-1157. doi: 10.7540/j.ynu.20190018
引用本文: 汤振兵, 王喜志, 孙亚茹, 马良财. 贵金属合金单原子链结构稳定性的第一性原理研究[J]. 云南大学学报(自然科学版), 2019, 41(6): 1152-1157. doi: 10.7540/j.ynu.20190018
TANG Zhen-bing, WANG Xi-zhi, SUN Ya-ru, MA Liang-cai. A study on first−principle of the structural stability of noble−metal alloy monoatomic chains[J]. Journal of Yunnan University: Natural Sciences Edition, 2019, 41(6): 1152-1157. DOI: 10.7540/j.ynu.20190018
Citation: TANG Zhen-bing, WANG Xi-zhi, SUN Ya-ru, MA Liang-cai. A study on first−principle of the structural stability of noble−metal alloy monoatomic chains[J]. Journal of Yunnan University: Natural Sciences Edition, 2019, 41(6): 1152-1157. DOI: 10.7540/j.ynu.20190018

贵金属合金单原子链结构稳定性的第一性原理研究

A study on first−principle of the structural stability of noble−metal alloy monoatomic chains

  • 摘要: 利用第一性原理计算方法,系统地研究了平面锯齿型贵金属Au−Ag、Au−Cu和Ag−Cu合金单原子链的结构稳定性. 采用弦张力标准而非传统的能量标准确定合金单原子链的稳定性,有限长悬空Au−Ag和Au−Cu合金单原子链的弦张力在轴向原子间距分别为0.24nm和0.23nm时出现极小值,所对应的锯齿型结构稳定性较高,而悬空Ag−Cu合金单原子链的弦张力不存在极小值,因此在实验上是不易制备的. 计算结果表明Au元素的相对论性效应和两尖端电极间弦张力的共同作用可以有效抑制纳米材料的“自净效应”,从而导致稳定Au−Ag和Au−Cu合金单原子链的形成.

     

    Abstract: The structural stability of Au−Ag, Au−Cu and Ag−Cu alloy monoatomic chains have been systematically investigated via first−principles calculations. We used the string tensioncriterion, rather than the energycriterion, to measure and identify the stability of tip−suspendedand finite alloy chains. We have found that the tip−suspended Ag−Au and Cu−Au alloy monoatomic chains are of stable zigzag structures due to the existence of local minima in the string tensions variation with their z−projected interatomic distance. However, a tip−suspended Ag−Cualloy monoatomic chain would be difficult to form in future experiments due to the nonexistent of local minima in the string tensions. We have also found that both the relativistic effect of elemental gold and the string tension applied by the tip contacts play important roles in suppressing effectively the self-purification effect, leading to the formation of the Au−Ag and Au−Cu alloy monoatomic chains.

     

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