C_(60),C_(180)和C_(60)@C_(180)富勒稀分子的电子传输特性

Electronic Transmission of C_(60),C_(180) and C_(60)@C_(180) Fullerene Molecules

采用扩展的Hückel方法与格林函数方法,研究了Au电极作用下,C60,C180和C60@C180富勒稀分子的电子结构与导电性,并对它们的电子结构与电子输运特性进行了对比.研究表明,C60,C180和C60@C180富勒稀分子与Au电极'接触'后,其HOMO,LUMO间的能隙减小;C60,C180和C60@C180富勒稀分子与Au电极之间的结合既有共价键的成分,又有离子键的成分.其中C60@C180分子与Au电极结合的离子键特征更为明显;当外加电压为1.2～3.0 V时,3种富勒稀的电导率及电流的大小排序为C180＞C60＞C60@C180,当外加电压为0～0.8 V和3.7～5.0 V时,它们的电导率及电流的大小排序则为C60＞C180＞C60@C180.

The extend Hiickel method and Green's function were used to analyze the electronic structure and the electronic transmission of the C60, C180 and C60@C180 fullerenes under the action of Au-electrodes. According to the calculated results, the differences of their electronic structure and electronic transmission were discussed. The results show that due to the intervention of the Au electrodes to the C60, C180 and C60@C180 molecules, their energy-level gaps between the LUMO and HOMO become narrow. The coalescent between the Au electrodes and the C60, C180 or C60@C180 molecule includes covalent bond and electrovalent bond. The coalescent between the Au electrodes and the C60@C180 molecule is significant electrovalent bond. The conductivities of the three electrode-fullerene molecule-electrode systems conform to the order of C180 > C60 > C60@C180 when the external voltage is in the range of 1.2 to 3.0 V and C60 > C180 > C60@C180 when the external voltage is in the range of 0 to 0.8 V and 3.7 to 5.0 V.