一维扩展离子Hubbard模型的相图研究?
Phase diagram of the one-dimensional extended ionic Hubbard mo del
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摘要: 应用密度矩阵重整化群方法,研究了存在交错离子势?时一维半满扩展Hubbard模型的相图。通过计算关联函数、结构因子、位置算符等方法,描绘了从Mott绝缘体-键有序绝缘体-Band绝缘体的特性并给出了精确的相边界。研究发现:中间的键有序绝缘体相在相图中占据了很小的一部分区域,当存在离子势?的情况下,这个区域将会有所增大;而当相互作用足够强时,这个中间相消失。给出了离子Hubbard模型(最近邻电子-电子相互作用V =0)的相图。Abstract: We use a density-matrix renormalization group method to study quantitatively the phase diagram of the half-filled one-dimensional (1D) extended Hubbard model in the presence of a staggered ionic potential?. An extensive finite-size scaling analysis is carried out on the relevant structure factors and localization operator to characterize the Mott-insulator (MI)-bond-ordered insulator (BOI)-band-insulator (BI) transitions. The intermediate BOI phase occupies a small region of the phase diagram, and this region is enlarged in the presence of?. In addition, the phase diagram of ionic Hubbard (the nearest-neighbor electron-electron interaction V =0) is also given.
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