摘要
在Su-Schrieffer-Heeger(SSH)模型基础上,计入长程电子关联的影响,研究聚乙炔分子链中双激子态与2个单激子态的稳态性质,比较不同关联强度下激子的晶格位形、能级、电荷密度波、自旋密度波以及吸收谱线。结果表明:零电子关联下分子链中的2个单激子不能稳定存在;激子半径均随着关联强度的增加而减小;与双激子的2个能级精细结构相比,2个单激子的能隙出现4个精细结构;2类激子的电荷密度波、自旋密度波与吸收谱线均随关联强度变化,并呈现显著区别。以上结果为区分分子链中2类激子的行为提供了依据,结果显示在激子行为中必须考虑电子与其的关联性。
Adding a extended Hubbard term to the SSH model for polyacetylene, we carried a self-consistent variation calculation on biexciton and two single-excitons in polyacetylene. The configuration,energy level, charge density wave, spin density wave and absorbance in the two systems are compared. Results show that the two single-excitons can not exist stablely without electronic correlation; radiuses of biexitons and single-excitons decrease as the electronic correlation increases;two single-excitons system has four energy levels in the energy gap, while biexciton system has only two; charge density wave, spin density wave and absorbance of the two systems all change according to the electronic correlation and with marked differences. The facts offer a criterion to distinguish the two kinds of exciton, and show that the electronic correlation must be considered in excitons behavior.
出处
《河北科技大学学报》
CAS
北大核心
2011年第4期308-312,325,共6页
Journal of Hebei University of Science and Technology
基金
海南师范大学青年教师基金资助项目(QN0803)
关键词
双激子
单激子
电子关联
能级
电荷密度波
自旋密度波
biexciton
exciton
electronic correlation
energy level
charge density wave
spin density wave