中国物理B ›› 2001, Vol. 10 ›› Issue (5): 384-389.doi: 10.1088/1009-1963/10/5/304

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VARIATIONAL STUDY ON MISSING BOND-CHARGE REPULSION ON THE EXTENDED HUBBARD MODEL: EFFECTS ON POLYACETYLENE

孙磊, 章豫梅, 冯伟国   

  1. Department of Physics, Tongji University, Shanghai 200092, China
  • 收稿日期:2000-07-19 修回日期:2001-01-10 出版日期:2001-05-15 发布日期:2005-06-12

VARIATIONAL STUDY ON MISSING BOND-CHARGE REPULSION ON THE EXTENDED HUBBARD MODEL: EFFECTS ON POLYACETYLENE

Sun Lei (孙磊), Zhang Yu-mei (章豫梅), Feng Wei-guo (冯伟国)   

  1. Department of Physics, Tongji University, Shanghai 200092, China
  • Received:2000-07-19 Revised:2001-01-10 Online:2001-05-15 Published:2005-06-12

摘要: The variational approach is applied to the study on the effect of Coulomb interaction between electrons on the dimerization in a one-dimensional commensurability-two Peierls system, such as trans-polyacetylene. For the case of omitting direct repulsion between electrons in the bonds between sites W, it is confirmed that the weak interactions tend to enhance the dimerization; but when W is included, this enhancement will be attenuated. If |W| is sufficiently large, the net effect of electron-electron interactions will reduce the magnitude of the electron-phonon-induced dimerization.

Abstract: The variational approach is applied to the study on the effect of Coulomb interaction between electrons on the dimerization in a one-dimensional commensurability-two Peierls system, such as trans-polyacetylene. For the case of omitting direct repulsion between electrons in the bonds between sites W, it is confirmed that the weak interactions tend to enhance the dimerization; but when W is included, this enhancement will be attenuated. If |W| is sufficiently large, the net effect of electron-electron interactions will reduce the magnitude of the electron-phonon-induced dimerization.

Key words: Fermi systems, Hubbard model

中图分类号:  (Lattice fermion models (Hubbard model, etc.))

  • 71.10.Fd
02.30.Xx (Calculus of variations) 61.50.Lt (Crystal binding; cohesive energy)