Quantum critical behavior of the one-dimensional ionic Hubbard model
Abstract
We study the zero-temperature phase diagram of the half-filled one-dimensional ionic Hubbard model. This model is governed by the interplay of the on-site Coulomb repulsion and an alternating one-particle potential. Various many-body energy gaps, the charge-density-wave and bond-order parameters, the electric as well as the bond-order susceptibilities, and the density-density correlation function are calculated using the density-matrix renormalization group method. In order to obtain a comprehensive picture, we investigate systems with open as well as periodic boundary conditions and study the physical properties in different sectors of the phase diagram. A careful finite-size scaling analysis leads to results which give strong evidence in favor of a scenario with two quantum critical points and an intermediate spontaneously dimerized phase. Our results indicate that the phase transitions are continuous. Using a scaling ansatz we are able to read off critical exponents at the first critical point. In contrast to a bosonization approach, we do not find Ising critical exponents. We show that the low-energy physics of the strong coupling phase can only partly be understood in terms of the strong coupling behavior of the ordinary Hubbard model.
Cite
@article{arxiv.cond-mat/0307741,
title = {Quantum critical behavior of the one-dimensional ionic Hubbard model},
author = {S. R. Manmana and V. Meden and R. M. Noack and K. Schoenhammer},
journal= {arXiv preprint arXiv:cond-mat/0307741},
year = {2009}
}
Comments
18 pages, 16 figures, submitted to Phys. Rev. B