掺杂聚乙炔中的边界效应与孤子对稳定性

在自然边界条件下,研究了含有两个杂质离子的反式聚乙炔链中孤子对的稳定性和电子能级结构。所用哈密顿量在SSH模型基础上,附加了一个端点势,并包含了杂质的屏蔽库仑势及格点上e-e相互作用。计算结果显示,杂质离子的库仑作用力程足够长时,链中形成稳定的孤子对,链端的影响增强这种稳定性。带隙宽度随链的增长而变窄,但孤子能级至导带底的跃迁能量随链长变化不明显。关键词：

BOUNDARY EFFECTS ON THE STABILITY OF THE SOLITON PAIRS IN A DOPED POLYACETYLENE CHAIN

The stability of soliton pairs and the electronic energy level structures in a doped poly-acetylene chain have been studied under natural boundary conditiono. In the Itamiltanian usel an end point potential was added to the SHH model, and the screened Coulomb potential of impurities and e-e interaetion on the tattice points were also indndelincluded. The caleulated results Show that, as the range of coulomb interaction is long enongh, stable soliton pairs are formel in the chain, and the stability is enlanced by the influce of the ends the gap width becomes narrow with the increase of chain length. But the deplndence of transition energg from soliton level to band bottom on chain length is not very signicant.