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arXiv 1108.0801cond-mat.mes-hall
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吸附和缺陷对金纳米管电子和输运性质的影响

Adsorbate and defect effects on electronic and transport properties of gold nanotubes

Yongqing Cai, Miao Zhou, Minggang Zeng, Chun Zhang, Yuan Ping Feng

摘要:

采用第一性原理计算研究了吸附物(CO分子和O原子)和缺陷对Au纳米管(Au(5,3)和Au(5,5))电子结构和输运性质的影响.对于CO吸附,考虑了Au管上CO的各种吸附位点。CO分子的振动频率在Au(5,3)的两种近简并稳定吸附构型中有很大的不同,这意味着通过测量CO的振动频率来区分这两种构型的可能性。CO吸附后,Au(5,3)的电导降低了0.9G0,Au(5,5)的电导降低了约0.5G0。对于O-吸附的Au管,O原子与Au管强烈相互作用,导致两个Au管的电导下降约2G。这些结果可能对基于Au管的化学传感具有影响。当存在单空位缺陷时,我们发现,对于这两个管,电导降低约1G 0。另一种类型的缺陷所产生的一个Au原子的粘附也被认为是。对于这种情况,发现对于Au(5,3)管,缺陷使电导降低近1G_0,而对于Au(5,5)管,电导的降低仅为0.3G_0。

英文摘要:

First-principles calculations have been performed to study the effects of adsorbates (CO molecules and O atoms) and defects on electronic structures and transport properties of Au nanotubes (Au(5, 3) and Au(5, 5)). For CO adsorption, various adsorption sites of CO on the Au tubes were considered. The vibrational frequency of the CO molecule was found to be very different for two nearly degenerate stable adsorption configurations of Au(5, 3), implying the possibility of distinguishing these two configurations via measuring the vibrational frequency of CO in experiments. After CO adsorption, the conductance of Au(5, 3) decreases by 0.9G0 and the conductance of Au(5, 5) decreases by approximately 0.5G0. For O-adsorbed Au tubes, O atoms strongly interact with Au tubes, leading to around 2G0 of drop in conductance for both Au tubes. These results may have implications for Au-tube-based chemical sensing. When a monovacancy defect is present, we found that, for both tubes, the conductance decreases by around 1G0. Another type of defect arising from the adhesion of one Au atom is also considered. For this case, it is found that, for the Au(5, 3) tube, the defect decreases the conductance by nearly 1G0, whereas for Au(5, 5), the decrease in conductance is only 0.3G0.

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