Static versus dynamic fluctuations in the one-dimensional extended Hubbard model
|Title||Static versus dynamic fluctuations in the one-dimensional extended Hubbard model|
|Publication Type||Journal Article|
|Year of Publication||2007|
|Authors||Craig, H. A., Varney C. N., Pickett W. E., and Scalettar R. T.|
|Journal||Physical Review B (Condensed Matter and Materials Physics)|
|Keywords||antiferromagnetism, charge density waves, Hubbard model, lattice dynamics, Monte Carlo methods, spin density waves, spin fluctuations, total energy|
The extended Hubbard Hamiltonian is a widely accepted model for uncovering the effects of strong correlations on the phase diagram of low-dimensional systems, and a variety of theoretical techniques have been applied to it. In this paper the world-line quantum Monte Carlo method is used to study spin, charge, and bond order correlations of the one-dimensional extended Hubbard model in the presence of coupling to the lattice. A static alternating lattice distortion (the ionic Hubbard model) leads to enhanced charge density wave correlations at the expense of antiferromagnetic order. When the lattice degrees of freedom are dynamic (the Hubbard-Holstein model), we show that a similar effect occurs even though the charge asymmetry must arise spontaneously. Although the evolution of the total energy with lattice coupling is smooth, the individual components exhibit sharp crossovers at the phase boundaries. Finally, we observe a tendency for bond order in the region between the charge and spin density wave phases.