Hubbard电子强关联与site-type杂质势对反式聚乙炔电子态的影响

EFFECTS OF HUBBARD INTERACTION AND SITE-TYPE IMPURITY POTENTIAL ON ELECTRONIC STATES IN TRANS-POLYACETYLENE

本文在苏武沛、Schrieffer和Heeger(SSH)模型的基础上,分别考虑site-type杂质势和Hubbard电子强关联的作用,计算了反式聚乙炔链的电子能谱、本征矢和序参量。结果发现,杂质势对孤子有较强的钉扎作用,它破坏了电子能谱对称性,并使midgap态发生移动,这与Hubbard电子强关联对孤子能级的影响根本不同。值得指出的是,只有同时考虑site-type杂质势和Hubbard相互作用,才能对聚乙炔的掺杂光吸收实验做出正确的理论解释。

In this paper, the SSH mode] has been extended to include the site-type impurity potential and the Hubbard interaction. The energy spectra and the electronic states of soliton in transpolyacetylene have been studied by the self-consistent iterative approach. Our numerical calculations have shown that the important differences in the effects of impurity potential and Hubbard interaction on electronic states of soliton. Namely, the site-type impurity potential is to shift the midgap states of the charged solitons in the opposite direction with Hubbafd interaction. Our conclusion are coincident with experimental results