掺杂反式聚乙炔中Site-type杂质势的唯象模型

The Phenomenological Models of Site-type Impurity Potential in Doped Trans-Polyacetylene

利用SSH模型讨论了Site-type杂质势对反式聚乙炔(trans-PA)电子态的影响。具体计算表明:对各向同性情况,Site-fype杂质势破坏了电子能谱的对称性,并使孤子能级发生移动,随着杂质离子与反式聚乙炔链间距的变化,它将引起孤子能级的变动。但不影响孤子局域化程度;而各向异性Site-type杂质势的不均匀性对trans-PA的电子能谱及孤子局域化程度影响较大。

The effects of Site-type impurity potential which includes isotropic andanisotropic conditions on the electronic states in doped trans-polyacetylene havebeen calculated numerically by SSH model.For isotropic condition,the resultshave shown that the Site-type impurity potential can break down the symmetry ofmidgap state.In addition,changing the spacing of charged impurity ions to thechain only causes the variation of soliton state,however,the degree of localizationof soliton is not changed at all.Further study has indicated that a marked variationin the electronic states of trans-PA is caused by the anisotropic impurity potential.In particular,when the magnitude of the anisotropic degree γ is larger than 2.5,the degree of localization for these soliton states decreases rapidly.