Abstract
We present a determinant quantum Monte Carlo study of the competition between instantaneous on-site Coulomb repulsion and retarded phonon-mediated attraction between electrons, as described by the two-dimensional Hubbard-Holstein model. At half filling, we find a strong competition between antiferromagnetism (AFM) and charge-density-wave (CDW) order. We demonstrate that a simple picture of AFM-CDW competition that incorporates the phonon-mediated attraction into an effective-U Hubbard model requires significant refinement. Specifically, retardation effects slow the onset of charge order so that CDW order remains absent even when the effective U is negative. This delay opens a window where neither AFM nor CDW order is well established and where there are signatures of a possible metallic phase.
Original language | English (US) |
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Article number | 246404 |
Journal | Physical Review Letters |
Volume | 109 |
Issue number | 24 |
DOIs | |
State | Published - Dec 10 2012 |
Externally published | Yes |
All Science Journal Classification (ASJC) codes
- General Physics and Astronomy