• 主题
高级搜索  >
历史搜索 清空历史
首页> 美国政府科技报告 >Off-Diagonal Coulomb Interactions in the Extended Peierls-Hubbard Model: Exact Diagonalization Results.
【24h】

Off-Diagonal Coulomb Interactions in the Extended Peierls-Hubbard Model: Exact Diagonalization Results.

机译：扩展peierls-Hubbard模型中的非对角库仑相互作用：精确对角化结果。

获取原文
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

For conjugated polymers, the extended Peierls-Hubbard model has been widely accepted as correctly incorporating the effects of both e-p and e-e interactions. In the absence of e-e interactions, the ground state of (CH)(sub x) is the 2k(sub F) bond-order wave (BOW) -- dimerization/bond alternation -- predicted by Peierls theorem. It is now well established that for the weak e-p coupling appropriate to (CH)(sub x), the on-site Coulomb repulsion actually enhances dimerization up to fairly large values (U > 6t(sub 0)). These results are still widely regarded as counter to the conventional wisdom that Coulomb interactions should suppress the build-up of charge anywhere, on the sites or on the bonds. Since the extended Peierls-Hubbard model incorporates only (lattice) site-diagonal parts of the electron-electron interactions (U, V), and omits the off-diagonal bond-charge repulsions (W,X), it is natural to ask whether this model adequately describes the full consequences of e-e interactions. In the specific context of (CH)(sub x), the potential importance of this omission is readily recognized. Intuitively, the bond-charge repulsion should suppress dimerization, since it opposes the build-up of charge on the bonds. Thus, the absence of W and X terms in the standard extended Peierls-Hubbard models suggests a priori that these models may artificially favor the continuation of dimerization in the half-filled band into the region of intermediate to strong Coulomb interaction. More generally, the omission of terms such as W and X raises significant questions about the appropriateness of Hubbard models for describing e-e interactions in the whole class of novel solid state materials. Thus this issue is extremely important and is, discussed further in this paper. 14 refs., 6 figs.

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号