【摘要】 采用基于密度泛函理论(DFT)的第一性原理研究了合金团簇(PbSn)n(n=1～10)的稳定性及金属性.结果显示:同比例铅锡合金团簇具有与单质铅、锡团簇相同的幻数尺寸,但结构特点却与单质团簇不同,铅、锡原子间首先各自形成单质团簇,然后再结合成合金团簇,且表现出松散型与密堆积型的有机结合.另外,(PbSn)n(n=1～10)团簇构型在N=14处发生突变:类似于密堆积构型向层状转变,同时HOMO-LUMO能隙具有先增大后减小的趋势,并出现微弱的半导体向金属转变的行为,而且团簇原子总数为20的HOMO-LUMO能隙较相同尺寸单质团簇的还低,说明合金团簇具有比单质团簇更好的导电性.更多还原

【Abstract】 By using the first-principles calculations based on density functional theory,the evolution of the lowest energy structure,binding energy and electronic structure of(PbSn) n(n=1~10) alloy clusters are comprehensively investigated.It is shown that the same ratio alloy clusters have uniform Magic size with pure Pb、Sn clusters,but their geometry structure characteristic(firstly,the Pb and Sn atoms come into being pure clusters respectively,then they are used to build alloy clusters) is different from homogeneous Pb、Sn clusters,and these configurations of alloy clusters are constructed by loose and close-packed structures at the same time.Moreover,the structural transformation from close packed to layered occurs at the total atom number N=14.These calculations also reveal that the HOMO-LUMO energy gap appears first increased and then decreased,which indicates weak transformation from semiconductor to metallicity.And the Gap is smaller than those of pure Pb、Sn clusters with N=20,which illuminates that the conductivity of same proportion alloy cluster is better than pure cluster in 20 atoms.更多还原