摘要
从离散的ＳＳＨ模型出发，考虑了链内的电子相互作用，以及由杂质和周围链上的荷电孤子产生的库仑势的影响，探讨了各种掺杂浓度的反式聚乙炔中孤子晶格的能谱与电子束缚态。计算结果表明：在孤子晶格的能谱中，在价带底有两条定域能级，在导带顶存在着多个电子束缚态，随掺杂浓度的升高，束缚态的局域性减弱，禁带中的孤子能级形成孤子能带。当掺杂浓度高达１６．６７％时，所有的电子束缚态都消失，转变为扩展态。孤子晶格的禁带宽度随着掺杂浓度的增加而增大，最高占据态与导带底之间的能隙则随之逐渐减小。孤子能带底与价带顶之间的能隙在临界浓度附近有一极大值。还讨论了电子－电子相互作用对孤子晶格能谱的影响。
tarting from the extensional discrete model SSH Hamiltonian containing an ex-ternal Coulomb potential arising from interchain charged solitons and the counteri-ons,the intrachain electron-electron interaction, the energy spectra and electron sta-tes of soliton lattice have been studied in trans-polyacetylene. The results show that:two bound states have been found at the bottom of valence band and several otherstates at the top of conduction band.With the increasing of the dopant concentra-tion,the localization of bound states are weakened and the discrete soliton energylevels in the forbidden band move into the soliton band. When the dopant concentra-tion is up to 16.67 % ,all the discrete electron states of soliton lattice disappear andbecome extended ones.It is found that the forbidden band width increases and thegap(between the top of the soliton band and the bottom of conduction band)na-rrows with the doping level increasing.Furthermore,the gap(from the bottom ofthe soliton band to the top of valence band)has a maximum at the critical dopinglevel.Finally,the effect of e-e interaction on the energy spectra of soliton latticeis discussed.
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
1994年第9期1502-1506,共5页
Acta Physica Sinica
基金
国家自然科学基金
